A century of MI5 and MI6

Surely we've had spies for longer?
Yes, it's an ancient trade. MI5's crest includes the red rose of Sir Francis Walsingham, who in the 16th century despatched Elizabeth I's "intelligencers" across Europe. But Britain's modern-day espionage began in the build-up to the First World War, when the Government was convinced that German spies were watching Britain's ports. In October 1909, the War Office and the Admiralty set up a new Secret Service Bureau, that had a Home Section and a Foreign Section. The Home Section, called MI5, reported personally to the Home Secretary. The Foreign Section reported to the Foreign Secretary and was later known as MI6, but its official name is the Secret Intelligence Service (SIS). The first director of MI6 was Captain Mansfield Cumming, who initialled his papers "C" in green ink, thereby creating the nickname for all successive directors.

Was there much German spying in 1909?
"Espionage is carried out wholesale in East Anglia, as is well known by everyone who rides a bicycle about those counties in the summer," wrote a War Office official shortly before the First World War. In reality it wasn't quite as bad as that: 35 German spies were uncovered in Britain during that war. Eleven were executed. MI6's early missions abroad were not successful, but both agencies grew rapidly during the War, with MI5's staff rising from 10 to 844 by the Armistice. MI6 took over the Government Code & Cypher School (now GCHQ), which turned its attention to cracking the codes of the new Bolshevik regime in Russia.

What did they do in peacetime?
MI6 watched Russia and Germany, successfully uncovering evidence of Nazi-Soviet cooperation on weapons in the Thirties, while MI5 began a task that would last much of the century: searching for communists. There were successes, such as the infiltration of the British Union of Fascists and the Communist Party, but also the first signs of spies meddling in domestic politics. In 1924, a letter purporting to come from the USSR's communist leadership, urging British socialists to revolt, was leaked to the press. The so called "Zinoviev Letter", later shown to be the work of MI5 and MI6, contributed to the fall of the first Labour government that same year.

And in the Second World War?
Though eclipsed by the work of new clandestine agencies such as the Special Operations Executive, MI6 excelled at code-breaking, notably the cracking of the German Enigma machine at Bletchley Park. MI5, for its part, "turned" German spies – catching and sending them back to feed false information to the Nazis. Before D-Day in 1944, a double agent codenamed "Garbo" – a Spaniard called Juan Pujol Garciá – helped fool the Germans into believing that the real landing point of the invasion was to be at Pas-de-Calais rather than Normandy. Before the War's end, however, both agencies had begun to focus on the Soviet Union. And that's when the trouble started.

Where was the trouble located?
In MI6's Soviet espionage section, whose first postwar head was Kim Philby, later to be awarded the Red Banner of Honour for his services to the KGB. During and after the War, Philby and the other members of the so-called "Cambridge Five" gave reams of top secret British and US information to the Russians. British agents sent to Albania and Ukraine to foment anti-communist revolution were executed. The credibility of MI6 suffered hugely after fellow spies Guy Burgess and Donald Maclean defected in the early Fifties – followed 12 years later by Philby. At the same time, huge pressure was put on MI5 to find how such traitors were recruited.

And how did MI5 go about it?
By searching for "subversives" wherever it could, infiltrating the CND, unions and student politics in the Sixties and Seventies, opening files on everyone from Lenin (Vladimir) to Lennon (John). Files were also kept on many Labour politicians, including Harriet Harman, Jack Straw and Peter Mandelson. "We bugged and burgled our way across London at the state's behest, while pompous bowler-hatted civil servants in Whitehall pretended to look the other way," wrote Peter Wright, a former MI5 officer in his banned book, Spycatcher, in 1985. By the Eighties, however, the emphasis was turning away from "subversion", though MI5 still made sure to target the leaders of the 1984-85 miners' strike.

What accounted for the change in emphasis?
Partly the fact that MI6 had managed to turn the tide on Moscow by recruiting Oleg Gordievsky, the KGB Colonel in charge of Soviet intelligence-gathering in the early Eighties; more generally, because communism was on the wane. Under Mrs Thatcher, who ordered a clean-up of MI5, the new priority became Northern Ireland. Both agencies also became more publicly visible. In 1992 Stella Rimington became the first head of MI5 to be identified to the public, and the Intelligence Services Act (1994) made the services more accountable to Parliament. However, the greatest change in direction for both agencies was caused by the rise of global terrorism in the Nineties, climaxing in the 9/11 attacks.  

And how have the two agencies changed as a result?
Both MI5 and MI6 have expanded rapidly to face the threat from al-Qaeda and homegrown terrorists. By 2011, MI5 should have 4,000 staff, more than double the 2001 quota. MI6 does not disclose its size, but the overall budget for Britain's intelligence agencies (MI5, MI6 and GCHQ) has risen to £2bn – from £992m in 2002. Yet for all the extra money and staff, neither agency has escaped controversy. Mohammad Sidique Khan, leader of the July 7 bombers, came to MI5's attention eight times before the attacks. Both services are also being investigated over allegations of complicity in torture: British officers are accused of being present at the abuse of terrorist suspects in Pakistan and colluding in brutal CIA interrogations – at Guantanamo Bay, among other places. ·