The University of Cambridge, which has for so long been considered a bastion of all that is good and right with the great country of England, has produced lovers, leaders, doctors, lawyers, researchers, academics and, of course, spies.

For many centuries the university was seen as a step on the ladder to the 'elite', moneyed classes whose job it was to administrate and manage the country's affairs. This had never been questioned and was widely accepted as 'the way it has always been'. In the 1930s, five young men met in its hallowed halls. These five men would go on to do much to tarnish Cambridge's reputation. They were:

• Donald McLean
• Guy Burgess
• Harold 'Kim' Philby
• Anthony Blunt
• The fifth and final man cannot be named until his death, though some believe him to be John Cairncross, who had links with the spies at Cambridge and was himself accused of being a Communist spy.

The damage that was done has still not been fully realised. At the time much of the blame for the fiasco was apportioned to the 'establishment'. Back then, forgiveness for almost anything was virtually guaranteed as long as you were part of the so-called 'Old Boy Network' - meaning that you went to the right kind of school, knew and mixed with the right kind of people, and married into the right family. It was part of a 'who you know, not what you know' culture that still exists to an extent today. In the case of Guy Burgess, it seemed that every time he disgraced himself his bosses gave him a more influential job, and Anthony Blunt was allowed to keep his job as Surveyor of the Queen's Pictures for 15 years after confessing to espionage for the Soviets. However, the story really starts in the years of the Great Depression.

After the Wall Street Crash of 1929 the world was plunged into economic crisis, precipitating mass unemployment, soup kitchens on many city streets, food queues and shortages of almost everything imaginable. Even the privileged classes were not entirely exempt. The Socialist groups on many university campuses were beginning to expand. This included a group at Cambridge. Many young people were fed up with capitalist ideals and wanted to find their own political voice, and so many young men went to fight for Franco and the Nationalist cause in the Spanish Civil War. Equally, many went to the Soviet Union to try Communism first-hand. Others, however, found a more clandestine way to help the Socialist cause.

Anthony Blunt

Anthony Blunt was the first of the five to enter Cambridge, arriving in 1926 to study History of Art. The son of a London vicar, he joined the 'Cambridge Apostles', a secret society which was strongly Marxist. In 1933 he went to Russia and it was probably there that he was recruited by the NKVD¹. He then became the KGB's chief 'talent spotter' as a member of the Apostles and a French tutor (a necessity for any young man wanting a job in the Foreign Office). A discreet homosexual (a lifestyle choice that was illegal until the late-1960s), he was the lover of a fellow Apostle, Guy de Moncey Burgess. There is a little uncertainty as to who recruited whom at this point, although it is generally thought that Blunt recruited the other members of the ring.

At the outbreak of war, Blunt was Deputy Director of the Courtauld Institute of Art. He volunteered for work in Military Intelligence but was rejected because of his Communist affiliations, but later was astonishingly given a job in MI5 on the recommendation of a friend. For the next five years he covertly undermined counter-espionage operations. Some of his first tasks for Moscow were providing them with the names of double agents in the KGB, detailing who was watching whom, and monitoring diplomatic pouches and telephone calls. He was also able to tell Moscow the work roster, so Moscow knew who was watching them. Later in the war he worked closely with former lover Guy Burgess, who was recruiting for Moscow from the neutral embassies of Scandinavia, Portugal and Spain. The two men met regularly in Blunt's rooms at the Courtauld Institute to prepare their reports for their bosses at the Kremlin.

At the end of the war, Blunt left MI5 with the permission of Moscow, presumably as they already had other adequate sources in the agency. However, he didn't leave the service of the KGB. Blunt's new job was Surveyor of the King's Pictures which was perfect cover for his job as a courier, since no one would suspect a member of the King's staff of running messages, collecting information, leaving money for spies and passing on gossip gleaned from chats with former MI5 friends.

He proved indispensable to Russia's frontline agents, as he proved to Kim Philby when Burgess and McLean disappeared to Moscow in 1951. Knowing that the authorities would want to search Burgess's flat, Blunt, who had a key, let them in. While they were searching, Blunt noticed three letters that would implicate both Burgess and Philby in spying, so he pocketed them before they could be found. Knowing that he would be interrogated, the Russians advised Blunt to defect. He refused as he was pleased with the prestige his new job at Buckingham Palace had brought him. He told the Russians that he could survive any interrogation, and indeed did so 11 times in the next 12 years, continuing to run messages for the KGB throughout. He even helped to reactivate Philby in 1954 before visiting him in Beirut.

In 1963 his luck ran out when a former university friend who had been offered a job as art consultant to President Kennedy decided to clear his conscience and confessed to providing Moscow with personal appraisals of American attitudes. He named Blunt as the Soviet agent who had recruited him. In 1964 Blunt was confronted with this accusation by MI5 interrogator Arthur Martin; he was told that the Attorney General had authorised his immunity from prosecution if he confessed. Blunt confessed, and MI5 accordingly wiped the slate clean. During his confession, Blunt provided MI5 with the names of people he'd recruited, while also giving misleading advice to protect the other members of the ring.

Many questions have been asked as to why he was given immunity. Did MI5 have enough evidence to convict him? If not did they call his bluff? Did they hope that he'd betray his colleagues and lead them to other spies, or was it because of his royal connections?

In 1946, he was asked to go to Germany to retrieve some papers. He never revealed what the mission was, but the following year he was presented with the Commander of the Royal Victorian Order and the mission may have also had something to do with his subsequent knighthood.

In 1956, it was revealed that Blunt's mission may have been to retrieve records of conversations between the Duke of Windsor and Adolf Hitler. Dragging the Royal Family into a spy scandal was not an option, so he was allowed to keep his job and his titles. This remained so until 1979, when Prime Minister Margaret Thatcher's hand was forced by a book being published about the Cambridge Spies. Blunt was publicly unmasked, stripped of his titles and died unmourned and disgraced in 1983.

Guy Burgess

Guy Francis de Moncey Burgess, the eccentric son of a naval commander, arrived at Cambridge in 1930 to study History. He joined the highly secretive Apostles society which is where he met Anthony Blunt. Burgess, a drinker and openly homosexual², was a bit of an embarrassment with his antics. During the 1930s he was personal assistant to Jack McNamara, a Conservative MP. He was a brilliant conversationalist and was able to make friends with the rich and influential easily despite his drinking and his homosexuality. He combined his work with McNamara with a job at the BBC, which brought him important contacts and gossip which he in turn passed on to Moscow. As war approached, he was sent on several secret missions to Europe, delivering messages to French leader Edouard Daladier and Italian dictator Benito Mussolini when British PM Neville Chamberlain had exhausted all diplomatic efforts to secure peace in Europe. Apart from keeping Moscow appraised of crucial developments in Western Europe, he used his high society gossip to ingratiate himself with the intelligence community. He was paid for each tip-off and in January 1939 his diligence paid off when MI6 offered him a full-time job.

The Secret Service was hopelessly understaffed at the beginning of the war, so one of Burgess's first jobs was to recruit 'the right men' for the job. His chosen hunting ground was the posh clubs and society parties of London's elite. By the 1950s, Burgess was showing signs of stress. His drinking had led to him being removed from his post in the Far East and he scandalised diplomats in Gibraltar with his outbursts about homosexuality and politics. However, his loutish behaviour was rewarded with a change of scenery, and he was posted to Washington, where Kim Philby took him under his wing and tried to straighten him out after years of hard drinking and wild living. It was something he'd later come to regret when he asked Burgess to run an errand for him.

Meanwhile, the net was closing in on Donald McLean. He was about to be unmasked as a spy, and Philby and the Russians knew he was liable to crack under interrogation. It was decided to send him to Moscow. Burgess was asked to make sure McLean stayed one step ahead of MI6, but back in London, the net was closing in. Burgess received a tip off about an interrogation, packed up his car, drove to McLean's house, and then drove both of them to Southampton. They turned up a few months later in Moscow. The original plan was for McLean to go by himself but he didn't want to go alone, so Burgess went with him. Guy Burgess died in 1963 after his drinking finally caught up with him. His final years in Russia were not happy - he was homesick and felt out of place in his new homeland.

Donald McLean

In 1931, Donald McLean, the shy, clever son of a puritanical Liberal MP, arrived at Cambridge to study French. He wrote an article in a university magazine denouncing 'the whole crack-brained criminal mess' of the capitalist society, yet in 1935 passed the entrance exam to the Foreign Office and was posted to Paris, where he established himself as a rising star of the Diplomatic Corps. In 1944, he was made Head of Chancery at the embassy in Washington. Moscow must have thought they had struck gold as secret communiqués between the Premiers of Britain, Canada and the USA passed across his desk, detailing the formation of NATO and other war tactics.

In 1947, Moscow were rubbing their hands with glee again as McLean became secretary of the combined Policy Committee dealing with the classified Manhattan Project. He knew who was doing what, when and why, and passed secret after secret to the Russians who had many spies working in Los Alamos. McLean had yet another advantage given to him - a pass which allowed him access to the US Atomic Energy Commission HQ unaccompanied. This was a privilege even the commander of the Energy Commission itself did not have.

By the early 1950s, McLean, like Burgess, was showing the strains of leading a double life. He too was drinking heavily and making indiscreet comments about himself and British policies, but instead of sacking him, the Foreign Office promoted him to a top job in Cairo when his anti-American stance became too much of an embarrassment. Once there, he was arrested by the police, then whisked back to London and given six months to sort himself out. After that he was appointed the head of the American Desk at the Foreign Office which gave him the chance to tell Moscow of the crucial decision to limit America's involvement in the Korean War.

In the years after the war, American intelligence concentrated on decoding Russian radio traffic known as the Venona Transcripts. This led to the uncovering of many of the Atom Bomb Spies at Los Alamos but it was too little, too late. In 1949, Russia exploded their first nuclear bomb. One of the most influential spies was codenamed 'Homer'. Soon, British and US intelligence had narrowed the list of 'Homer' suspects down to four. One of them was Donald McLean. Knowing that he would not withstand interrogation by MI6, Moscow instructed him to flee. With the help of his Cambridge friend, Guy Burgess, he arranged to go 'away for the weekend'. It was the last time either of them were seen until they reappeared a few months later in Moscow to the embarrassment of the British intelligence services. Donald McLean was given a job in the Soviet Foreign Office, eventually dying an unhappy man in 1983. His wife had joined him in Russia, but later left him for Kim Philby.

Kim Philby

Of the Cambridge spies, Kim Philby was the one who did the most damage. Many secret service personnel lost their lives thanks to his treachery. Harold Adrian Russell Philby, the son of an Arabian adventurer, nicknamed Kim after Rudyard Kipling's boy spy, arrived at Cambridge in 1929 to study History and Economics. He became a discreet but committed Communist, and in 1934 made a trip to Vienna to witness the pro-German government put down Socialist attempts to challenge the old order. He helped Communists in their escape and even went so far as to marry his landlady's daughter to help her flee Austria as a British subject.

In 1936, on the orders of Moscow, Philby tried to cultivate a conservative background, appearing at Anglo-German meetings and editing a pro-Hitler magazine. In 1937, he left for Spain to cover the Civil War first as a freelance journalist, and then for The Times, reporting the war from Franco's point of view. A shell hit the car he was travelling in, killing three other journalists and wounding Philby. Somewhat ironically, Franco gave him a bravery medal. In 1940, Guy Burgess introduced him to the head of MI6 and he was taken on. Making a decided impression on his bosses, he was given a key job in the Iberian section with orders to counter the Nazi spy threat in Spain and Portugal and to protect vital shipping in the Mediterranean.

In 1943 a young man working under Philby had an idea that would exploit the fact that the military top brass in Germany were losing faith in Hitler. He suggested exploiting the split before Germany surrendered. If the idea had been acted upon, it is likely that thousands of lives would have been saved and Eastern Europe would have been spared nearly 50 years of Soviet rule. Unfortunately, the idea got no further than Philby's desk - he stopped the idea circulating, knowing that Russia wanted Germany destroyed and unable to threaten them again.

In August 1945, the newly appointed Russian consul in Turkey approached British diplomats offering them a deal. He wanted £27,000 and asylum, and in return he would reveal to them Russia's spy operations in Turkey and the lowdown on Russia's entire espionage network. In addition, he would name the spies that the KGB had in the Foreign Office and in Counter Intelligence. Such unrivalled information was too hot for the diplomats in Istanbul to handle, so they passed it on to MI6. 20 days later, Intelligence Officer Kim Philby arrived in Istanbul, apologising for the delay. The Russian diplomat never contacted them again. The reason became clear when a Soviet military plane touched down at the airport. A heavily bandaged figure was rushed aboard and the plane took off back to Russia. The diplomat had been betrayed by one of the moles he was planning to unmask.

The Kremlin were once again rubbing their hands with glee when, in 1944, MI6 promoted Philby to head of Russian Espionage. His treachery was making any attempt to spy on Russia useless as any British agent was caught and shot due to details that he provided. Philby also managed to keep a lid on all of the other agents that the KGB had in high places. In 1949, Philby was in Washington as the MI6 liaison to the CIA. The two agencies launched an attempt to start a revolution in Soviet influenced Albania. Exiled King Zog had offered his troops and other volunteers to help, but for three years every attempt to land in Albania was met with Russian ambushes. The Soviets even knew the emergency radio drill. Philby's betrayal cost 300 Albanian lives, and the same thing happened in a similar operation in the Ukraine. Couriers were disappearing, and Russian propaganda was coming out.

After these two disasters, the CIA and MI6 gave up meddling in Soviet affairs. Philby was also able to tell Moscow just how much the CIA knew about its operations. Moscow asked Philby not to bother saving spies who had served their purpose, but he sat on several reports naming Soviet spies anyway. In 1950 he was asked to help track down a spy codenamed 'Homer'. Knowing him from the start to be old university friend Donald McLean, it was Philby that tipped him the wink in 1951, leading to his two friends' defection and ultimately to his downfall.

Philby was instantly suspected of helping Burgess and McLean to escape as he was a friend and colleague of both men. Moscow was gambling on his ability to bluff his way out of anything. Even his Soviet superiors were amazed at the way he was able to save his skin. MI6 were reluctant to believe that Philby worked for the KGB, but MI5 were almost positive. They began to re-evaluate his career record, asking awkward questions about operations that had gone wrong. The CIA were also certain of his guilt, and the head of MI6 was given an ultimatum - sack him, or else.

Philby resigned from the Foreign Service, meaning that he could no longer work abroad, although he still did a little undercover work from time to time. In 1952 he was interrogated at length, stalling them with his life long stutter, Philby gave himself time to think and succeeded. MI5 couldn't convict him with the evidence that they had.

Philby was now flitting between jobs, still working for MI6 occasionally. Friends were helping him out when he was short of money, but he seemed reluctant to try and rebuild his life, he seemed to be waiting for something to happen. In 1955, it did. The Government published its White Paper on the disappearance of Burgess and McLean. It was a complete whitewash that one MP dismissed as 'an insult to the intelligence of the country'. An MI5 man furious at the omission of Philby's name decided to force the issue another way. He couldn't call Philby a spy outside Parliament without facing a writ for libel, but statements made in the House of Commons can be reported in the press however libellous. Journalists briefed by the MI5 man approached an opposition MP. He asked Prime Minister Sir Anthony Eden:

Have you made up your mind to cover up at all costs the dubious third man activities of Mr Harold Philby, who was the First Secretary at the Washington embassy a little time ago?

With that question asked, Philby's connection to Burgess and McLean was completed and a parliamentary debate was inevitable.

In the debate that followed, Foreign Minister Harold Macmillan responded to the Philby question as follows:

I have no reason to conclude that Mr Philby has at anytime betrayed the interests of this country, or to identify him with the so-called third man, if indeed there was one.

With this official blessing, Philby knew it was unsafe for anyone to call him a spy again. He held a press conference where he portrayed himself as an innocent man whose career had been ruined by his friendship with Burgess and McLean. Macmillan knew Philby was a traitor but couldn't prove it, so he ordered MI6 not to use him again. Unbelievably, MI6 ignored the Prime Minister and sent him to Beirut, where the Russians were trying to win favour in Egypt, Syria and the Gulf States. Philby travelled to the Middle East using a foreign correspondent's job for The Observer for cover. The CIA kept tabs on him while he was there.

In 1962, the CIA sent MI6 a very detailed debriefing of a Russian defector who named Philby as the man who tipped off Donald McLean and also as the man who led a KGB operation in the Arab States. The MI6 chief sent one of his agents to confront Philby, but first agreed with the Attorney General that Philby could be offered immunity from prosecution if he made a full confession. However, the KGB had already tipped Philby off about MI6's visit and had prepared an escape plan for him. He could not defect before the interrogation because it would endanger the source who warned the Russians of the danger to Philby. In the weeks leading up to his interrogation, Philby drank heavily but he was sober when the agent called on him. He began a carefully worded confession full of misleading sections designed to protect KGB moles in Britain. Philby signed the confession and the agent flew to America to check it with the CIA. Ten days later Philby and a female friend were on their way to a dinner party when he stopped the taxi saying he had to send a telegram to London and he would join the party later. He emerged in Moscow six months afterwards.

Like Burgess and McLean, Philby left behind more questions than he did answers. Moscow knew MI6 wanted him back in London for more questioning, so did they bring him to Russia because he was now more use to them in the KGB, or were they worried that 30 years of spying were beginning to take it's toll on him? Maybe it could have been because they'd learnt that the CIA had sent a sniper team to assassinate him?

Philby fared better in Moscow than Burgess and McLean. He was given a job as a senior KGB officer, and was also awarded the Order of the Red Banner and full Russian citizenship. His only contact with Britain was a daily copy of The Times, a special privilege granted by the Kremlin to allow him to could keep up with the English cricket scores. Western intelligence agencies began to detect Philby's hand in the planning of KGB offensives in the late 1960s and in 1979 he was spotted in Damascus. It was the first time he'd set foot outside Russia in 16 years. Kim Philby died and was buried with full military honours in Russia in 1988.

And Finally...

So what did the spies achieve? In the case of Burgess, McLean and Blunt, not a lot. Philby gained the most and was the most prolific of the spies, but McLean and other spies at Los Alamos helped the Russians produce their first nuclear weapon five years before the West predicted that they could. Philby was probably the truest and firmest believer in the Communist cause, less so the others. Once Moscow got hold, they wouldn't let go, which is probably why Burgess and McLean eventually turned to drink.

As it turned out, it was all for nothing. The fall of Communism probably began with the beginning of Solidarity in Poland in the late 1970s, then with the election of Mikhael Gorbachev in Russia in the 1980s. Gorbachev introduced more liberal policies, and when hard-line Communists tried to oust Gorbachev and were defeated, the Communist satellite states in Eastern Europe began to fall. The people of Hungary, Romania, East Germany, Bulgaria and others rose up and fought for their freedom. The end for Communism in Europe came in 1989, when the Berlin Wall finally came down. None of the Cambridge spies lived to see the final downfall of the cause they had all fought and lost so much for.

More from BBCi

• Further information on the BBC TV drama, Cambridge Spies.

• BBC Monitoring report on the story of Kim Philby's widow.

More from the Internet

• Visit the official site of MI5, the UK security service.