From his list Bystrolyotov targeted cipher clerks working in Geneva with the British delegation to the League of Nations. He assigned two agents to cultivate them, but one, an uncouth sailor named Basov, gave himself away. The other, Han Pieck, an urbane and articulate artist with a wide circle of cultured friends, speaking English without an American accent, was much more successful. He befriended Raymond Oake, code-named SHELLEY, invited him to visit his home in The Hague and eventually recruited him in London. The motive, as in the case of Oldham, was money: Oake had served fourteen years in the Foreign Office and still was listed as temporary employment without a chance for a pension. During the cultivation phase, a time of engaging conversation and social drinking, Oake introduced Pieck to another encrypter in Geneva, also in the FO, who proved as hard up for money as himself.

Captain John Herbert King was another "temporary" clerk without a pension or decent prospects for the future. Over beer with Pieck, he expressed himself as a disgruntled Irishman, a victim of English discrimination, under appreciated and underpaid. He had a son who deserved the best things in life and an American mistress whose tastes were not inexpensive. Pieck sympathized. He and his wife took King and his mistress on a paid vacation to Spain and made King hunger for the pleasures of high society. Then, when he could not afford them, Pieck made his pitch back in London. It was March 1935....

In July 1937 Maly was recalled to Moscow and his agents were put on ice, as they were considered tainted by his supposed ideological impurity. Thus, King was cold and invisible to counterintelligence for a period of time. Krivitsky would have known about this, as he was still with the apparatus in Paris when Maly went back to Moscow; but he had little information thereafter. He received a letter from Maly in August 1937, defected in October, then heard from Bassoff in Times Square a year and a half later that Maly was still alive. It was a lie: Maly had been executed at the end of 1937. Consequently, Krivitsky did not know whether Maly or a replacement had come back to England and reactivated King. Nor does the literature reveal King's status at the time that Levine pronounced his name to Lord Lothian. At the very least, if not currently working for the Bolsheviks, the code clerk was a dangerous "sleeper" ready for reactivation. Receiving the ambassador's urgent telegram, MI5 located the one man named King in the Communications Department and, as he was reportedly exhausted from work, gave him a two-week leave so as to facilitate a full-scale investigation and surveillance.

The anticipation of the chiefs at the Centre rose steadily through the early months of 1936 as their "mole" in the Foreign Office began relaying to the eager eyes in Moscow some of the British Government's most closely held diplomatic secrets. The NKVD archives disclose that this was not the first occasion the Soviet intelligence service had obtained access to confidential Foreign Office cables. Two cases of previous penetration - never admitted by the British - confirm that Maclean does not deserve the honour of being the first Soviet agent to penetrate the inner sanctums of the Foreign Office. This accolade actually belongs to an employee of the Communications Department named Ernest Holloway Oldham, a "walk in" to the Soviet embassy in Paris in 1929. A disaffected employee attached to a British trade delegation, Oldham offered to sell a Foreign Office cypher system for £12,000 only to find himself thrown out on his ear by the resident, a less than sophisticated Soviet intelligence officer by the name of Vladimir Voynovich. A former docker with a longshoreman's lack of vision he evidently suspected a British provocation plot. When Moscow identified the codes as genuine, Voynovich was reprimanded. The Centre dispatched an experienced "illegal", Dimitry Bystrolyotov, to re-establish contact with Oldham and apologize for his rough treatment. The painstaking search took this Russian colleague of Orlov's almost a year. When HANS, as Bystrolyotov was code-named, finally located the cypher clerk in 1930, he paid him £2,000 and put Oldham and his wife (who according to his report had seduced him) under Soviet control. Espionage proved too much, however, for Oldham. He resigned shortly before committing suicide in suspicious circumstances in 1933. Because of British secrecy, the significance of the Oldham case has remained undisclosed and underestimated. The truth, as revealed by NKVD, files is that Oldham was not just a code clerk but a cypher expert who developed codes and was therefore able to provide Moscow with a great deal of information on security and secret traffic systems. The resourceful Bystrolyotov, who operated under the alias of Hans Gallieni in England, had also obtained from Oldham not only the keys to unlock a considerable volume of British cypher cables but also the names of the other paid members of the Communications Department who became targets for Soviet recruitment.

One of the names passed to Moscow by Bystrolyotov was Captain John Herbert King, who was attached to the British League of Nations delegation in Geneva. Estranged from his wife and saddled with the burden of maintaining a free-spending American mistress, King was living way beyond his means. He became vulnerable to cultivation with Soviet money through expenses-paid Spanish holidays arranged by Henri Christian (Hans) Pieck, a Dutch artist, who was one of the NKVD's roster of agents in The Hague who were being run by Maly, the Centre's so-called "flying illegal". When King returned to London late in 1934, he began supplying Pieck with Foreign Office cables under the illusion that he was helping his friend's Dutch banker compile information on international trade relations. Assigned the code name MAG, King soon graduated to become a very valuable source for the Centre with his wholesale removal of copies of the Foreign Office cables he encoded, a role he continued to play until he was exposed by the Soviet defector Walter Krivitsky in the autumn of 1939. Information gleaned from Oldham and King enabled the Centre, with Maclean's help, to kick the door into the Foreign Office and its secrets wide open.'

The WAISE dossier reveals how, from the beginning of January 1936, when he handed his first bundle of Foreign Office papers to Deutsch, Maclean smuggled out an ever growing volume of documents. These were photographed overnight and handed back, to return the next morning. The volume soon became so great Deutsch instructed Maclean that, whenever possible, he should bring the documents out on a Friday night to give the overworked photographer of the "illegal" station two days to work before the papers were returned on Monday morning. The quantity and quality of the intelligence flowing from this source to Moscow picked up dramatically as Maclean gained both in expertise and confidence. No one in his office appeared to bother about the increasing amount of documentation he was ostensibly taking home to work on in his Chelsea bachelor flat in Oakley Street, a stone's throw from the Thames.

The reservoir of Foreign Office intelligence Maclean tapped opened up such a flood of documentation that Deutsch was soon overwhelmed. Following Orlov's departure, he had assumed the burden of heading the London "illegal" station and found it increasingly difficult to service Maclean in addition to taking care of the network, vetting new recruits and handling all the technical matters. Orlov's response to this overload on Deutsch was to send the INO Chief Slutsky a memorandum which concluded, "Taking into consideration the importance of the above-mentioned material and information that has fallen into our hands, in addition to the importance of other cultivations and recruitments that could benefit our field stations abroad, I consider the question of the Foreign Department's assigning an experienced and talented underground resident to head the field station in the British Isles to be extremely pressing.

Theodore Maly, one of the Centre's top agents, had by then been dispatched to England under the cryptonym MANN in January 1936 with sole responsibility for handling the material supplied by MAG, the code clerk King. The Chiefs did not immediately authorize him to give assistance to Deutsch's group. But, since Maly was a proficient and capable "illegal" who had experience in both counter-intelligence and agent operations, Orlov eventually prevailed on the Foreign Department. Maly was recalled to Moscow for briefing with Orlov and, by April 1936 had returned as the newly designated London resident with responsibility over Deutsch for the running and development of the Cambridge group.