The National Archives released 64 MI5 files from the immediate post-war period last week. The activities of Nazi intelligence agents, Soviet spies, right-wing extremists and Stalinist fellow travellers are all described in fascinating detail — two files refer to the unsuccessful attempt by Lehi (the Stern Gang) to blow up the Colonial Office on April 15, 1947.

On June 2, 1947, a 30-year-old man and his younger female companion were arrested at the French border en route to Antwerp. MI5 was informed that the woman possessed “a double-bottomed suitcase containing explosive powder, 14 pencil-shaped batteries, 7 detonators and a small watch containing a time bomb fuse”.

Moreover, the two bore a resemblance to the couple seen earlier at the Colonial Office. A fingerprint comparison confirmed them to be Gilbert Elisabeth Lazarus and Jacob Eliav — members of a Lehi team which resolved to carry the struggle of militant Zionists in Palestine into the heart of Whitehall. Lazarus, known also as Betty Knout, was sentenced to a year in prison while Eliav received eight months.

Jacob Eliav, alias Ya’akov “Yashka” Levstein, was known to the British as Lehi’s bomb maker — a man with a history of violence who was responsible for the deaths of many British personnel in Palestine during the previous decade.

He had escaped from a British military prison in December 1943 and made his way to Paris to head Lehi operations in Europe. It was the discovery of a bomb-making factory in a Paris apartment in May 1947 that made Levstein’s own arrest inevitable.

Ever since the bombing of the King David Hotel in July 1946, MI5 expected a wave of attacks in Britain. Sir Percy Sillitoe, the head of MI5, had handed a report entitled “Threatened Jewish Activity in the UK, Palestine and Elsewhere” to Prime Minister Clement Attlee and suggested Ernest Bevin, the Foreign Secretary, was a prime target for assassination. The members of Lehi were described as “desperate men and women who count their own lives cheap”.

MI5 also relied upon the Jewish Agency and British Zionist organisations to pass on any information about Lehi activities — many British Jews did not want violence to spill over from Jerusalem. MI5 applied for Home Office warrants to intercept correspondence and to tap telephones of “all the important Zionist organisations in Britain”.

Brought to Palestine as a child from Russia, Ya’akov Levstein had studied chemistry at the Hebrew University in the 1930s. In early 1939 he attended a training camp in the Tatra mountains near Slovakia for Irgun Zvai Leumi members, organised by the Polish military.

This had been initiated by Avraham Stern, the husband of his cousin and a leader of the Irgun. All this was unknown to Vladimir Jabotinsky, the hallowed leader of the Zionist Right, who placed his hopes in diplomacy and British fair play and whom Stern had compared to Hitler’s predecessor, Hindenberg — yesterday’s man.

Levstein and Stern were admirers of Boris Savinkov, the Russian social revolutionary who specialised in assassinations and acts of terror. On August 26, 1939, Inspector Ralph Cairns, head of the Jewish department of British intelligence in Palestine, and his friend, Ronald Barker, head of the Arab department, took their habitual Saturday afternoon stroll in Rehavia. They were blown to pieces by Levstein’s 15kg mine, placed hidden in the pathway — the Irgun accused Cairns of torturing prisoners.

Jews who worked for the British authorities — especially the intelligence services — were often targeted. So was T I Wilkin, a fluent Hebrew speaker and another head of the Jewish department of British intelligence.

Levstein was arrested with Stern a few days after the killing of Cairns and Barker. They were interned in Sarafand camp where Levstein helped Stern, an accomplished poet and classics scholar, to write poetry.

Yet these were difficult times for the Irgun. Jabotinsky had immediately declared his support for the Allies’ war effort in 1939 and many members of the Irgun followed his lead. Avraham Stern strongly rejected this approach.

Britain, he argued, had declared war against Nazi Germany, not to save the Jews but to defend its own national interests. Moreover, it was doing its utmost to bar the gates of Palestine to millions of desperate Jews trapped in Hitler’s Europe. In the summer of 1940, Stern signed Communiqué 112, regarded as the genesis of the group that the British labelled “the Stern Gang”, later known as Lehi.

Levstein enthusiastically followed Stern out of the Irgun into Lehi. Like Stern, he believed “the enemy of my enemy is my friend”. Could Nazi Germany therefore aid Lehi in driving the British out of Palestine? Before the onset of the Shoah, Stern understood Hitler as the latest in a long line of persecutors — not as an exterminator. Naftali Lubenchik was duly sent off to the German Legation in Beirut to explain Stern’s ideas — a visit facilitated and prepared by Ya’akov Levstein. Needless to say, Stern’s views failed to impress — Hitler was an ideological antisemite bent on destruction.

Out of prison, Stern needed funds. The Anglo-Palestine Bank was robbed in September 1940. Unlike the Irgun, which considered itself an underground army, Lehi had no such pretensions and promoted a policy of assassinations and killings. In January 1942 Levstein planned to kill leading British intelligence officers Morton and Wilkin by first creating a diversionary explosion. Levstein rationalised that the two men would turn up to investigate. Instead three Jewish officers, Schiff, Goldman and Dichter with another British inspector, Turton, reached the scene first. The young Lehi operator did not identify them and detonated Levstein’s mine. Their deaths in this botched operation turned the Jewish public in the Yishuv vehemently against Lehi.

A few days later an apartment in Tel Aviv’s Dizengoff Street was raided and two Lehi members shot dead by British police. Levstein was wounded and imprisoned. Stern met his end a few days afterwards when surrounded by Morton and armed policemen. Conflicting explanations about the manner of his death still abound. Levstein was asked to identify the body which he decidedly failed to do. Only when Stern’s family identified him was he taken away for burial.

Levstein survived to continue his activities after his escape from prison. In May 1946 he planned to kill Haj Amin al-Husseini, the Mufti of Jerusalem who had spent the war years in Berlin.

Levstein’s Lehi unit closely watched al-Husseini’s movements in Paris while the French deliberated whether to turn him over to the British. Levstein later wrote that “the best way was to blow up the Mufti in his car. I prepared a powerful mine that would not have left much of the Mufti”. Al-Husseini gave everyone the slip and escaped to Cairo.

Levstein and other members of Lehi, including future prime minister Yitzhak Shamir, eventually came in from the cold and were recruited by the Mossad in the 1950s.

Levstein lived to die in his bed in 1985. The revelations of these archives once again pose the inimitable question: freedom fighter or unscrupulous terrorist?

Lehi looked to the IRA as the model for its actions. In 1882 the Chief Secretary, Lord Cavendish, was murdered in Dublin. Oscar Wilde astutely commented at the time that “when liberty comes with hands dabbled in blood, it is hard to shake hands with her”.

Colin Shindler’s latest book, The Hebrew Republic: Israel’s Return to History is published by Rowman and Littlefield