Norman Moss - Klaus Fuchs - The Man Who Stole the Atom Bomb

Arnold sensed that there was an element of gameplaying in their friendship, that Fuchs was drawn towards confessing something. He had cultivated Fuchs’s friendship deliberately, but he was not the kind of man who can sit back coldly and manipulate someone else’s feelings. To some degree at least, the friendship was genuine on his part, although he would on occasions deny it. In a conversation years later, he struggled to explain his feeling for Fuchs. ‘I can’t call him a friend exactly, but I had affection for him… Well, was it affection? More than friendship, I felt sorry for him, because I knew for a long time how it had to end.’

Fuchs told Arnold he wanted to talk to him again about his father’s move, but he had nothing new to say, and he asked him again whether he would have to leave Harwell. The idea was becoming fixed in his mind that he would have to leave the place he loved. This was supposedly because of his father’s position, but there was also the thought somewhere in his mind that it would be in expiation of his own offences against Harwell. He told Arnold it would be easy for him to find a university post, but he did not make any move to do so.

What Fuchs did not know was that the security authorities were aware of his father’s move as soon as he was, because his mail was being intercepted and read and his telephone was being tapped. He was under suspicion.

The trail of suspicion that led to Fuchs began at Fort Meade, Maryland, a sprawling army camp situated roughly midway between Baltimore and Washington that was then the headquarters of the US Army Signal Corps. In the late 1940s, a special unit of the Signal Corps was operating behind a perimeter fence within the camp, in a cluster of buildings sprouting a baroque forest of aerials. This unit was intercepting messages sent by foreign governments, and decoding them. It was the predecessor of the National Security Agency, the agency for worldwide electronic eavesdropping that was established in 1952.

The Signal Corps had been intercepting messages between Soviet diplomatic missions in the United States and Moscow during World War II; the messages they intercepted were in code and they could not decipher them. But they kept them anyway, and the coded messages remained in the files, like packages waiting to be opened one day.

The means to open them came in the late 1940s with the discovery of some Soviet coding devices, which enabled cryptograph experts in America and Britain, working laboriously, to decode some Soviet messages. Decoders at Fort Meade applied these to messages that were currently being intercepted, and then to past messages in their files. [18] See Peter Wright’s book about MI5, Spycatcher .

Going through these, they found a message sent from the Soviet consulate in New York to Moscow in 1944 which, once decoded, seemed to concern atomic energy and a British scientist. It was given to the FBI, and also to the intelligence officer at the British Embassy in Washington, who passed it on to MI5.

The head of MI5’s counter-espionage branch, Dick White, took it to one of the heads of the atomic energy programme, Michael Perrin (now Sir Michael), who held the title of Deputy Director, Technical Policy. Perrin was a chemist who had come over to Tube Alloys from private industry during the war. He studied the message as decoded, and told White that it seemed to him to indicate that one Klaus Fuchs had given some information to the Russians while he was working on the atomic bomb project in New York.

This was in August 1949, and from then on Fuchs was under surveillance. MI5 put a tap on his telephone and intercepted his mail. Arnold was told. Meanwhile, MI5 analysed the message further, examining its context, and traced the movements of other British scientists who were working in New York. This process eliminated other suspects and pointed more clearly to Fuchs.

Perrin told the head of the atomic energy programme, the former RAF chief, Lord Portal of Hungerford, that there was now some doubt about Fuchs’s loyalty. He also told the chief civil servant at the Ministry of Supply. He told Sir John Cockcroft, and Cockcroft’s response was characteristic of his anxiety to avoid unpleasantness. He held up his hand and said to Perrin, ‘Don’t tell me any more! Thank God I’m sailing to America on the Queen Elizabeth tomorrow, and I can’t be got at.’

A few days after this, in the early hours of the morning of Saturday, 10 September, Perrin received a telephone call from Alec Longair, the Assistant Scientific Attaché at the British Embassy in Washington. Longair told him that a serious matter had arisen, and he was to go to the communications room at the American Embassy. ‘I’m on my way,’ Perrin said, and rolled out of bed and telephoned for a taxi. When he got there, he and a senior scientist from the Intelligence Service were put into contact with Longair and a number of Americans at the communications centre in the Pentagon (Longair was told that he was the first non-American ever to be admitted there). Communication was by coded telex messages that were flashed on to a screen.

The Americans said that a high-flying US Air Force detection aircraft had found traces of radioactivity in the upper atmosphere that they thought must have come from a Soviet atomic explosion. For two hours, they exchanged ideas on weather, wind patterns and levels of radioactivity. The radioactive cloud was now drifting over the North Atlantic, and the Americans wanted an RAF plane to go up and confirm the finding. Perrin said he thought there would be no difficulty about this. These exchanges, incidentally, are indicative of the British — American relationship at this time: Britain was still a world power and America’s closest and most powerful ally.

It turned out that there was a slight difficulty because the following day, a Sunday, was Battle of Britain Day; RAF airfields were to be open to the public, and the RAF was getting ready to show itself off. None the less, a Halifax bomber carrying detection equipment took off from Aldergrove Airport in Belfast. The flight confirmed the American finding, and this was reported to Perrin.

Perrin went to Prime Minister Clement Attlee with the report, accompanied by the head of MI6, the overseas Intelligence Service, Sir Stewart Menzies. Attlee received the news with his usual calm. He said he would send a message immediately to the Foreign Secretary, Ernest Bevin, who was in Washington. Perrin told him they would analyse the samples of radioactivity to learn what they could about the Soviet explosion.

Then he said: ‘There’s something you should know. One man at Harwell would be the best person to analyse these findings, a man named Klaus Fuchs. But there’s some doubt about his security position.’ This was the first time that Attlee heard Fuchs’s name.

He said to Menzies: ‘I assume this is being checked.’

Menzies replied, ‘Yes. But at the moment, we can’t use the evidence that we have.’

The radioactivity-sensitive filters from the Halifax bomber were sent down to Harwell and someone else was assigned to analyse them, in secret. Ten Downing Street and the White House made their joint announcement.

Arnold, meanwhile, was still having friendly chats with Fuchs, and was wondering how he should approach him about this matter. Fuchs came to him first, with his question about his father’s move to East Germany. The discovery of the intercept coincided with Fuchs’s own doubts about what he was doing.

It was these doubts that had prompted Fuchs to take up his father’s move with Arnold. Arguing with himself about whether he should leave Harwell as a penance for his actions, he went to Arnold to avoid having to answer the question. If Arnold said he would have to leave Harwell because his father was going to East Germany, then that would settle the matter.