Guillaume's book is curiously engaging, in spite of (or perhaps because of) its dubious provenance. But, some time between the collapse of the DDR in 1989 and his death in 1995, he gave a long interview to the journalist Guido Knopp, who was preparing a television programme about him, in which he cast even further doubt on it as a source. The ghost, he says, was 'a very nice journalist' supplied by the Stasi, who encouraged him to improve his stories somewhat. One of them, which had always puzzled me, about a meeting Guillaume claimed to have had in the Picasso Museum in Vallauris with 'a high-ranking man' in the intelligence service - presumably Wolf himself- he now disavowed completely. He also confessed to having built up the story of persuading Bauhaus to take the wrong dispatch-box back to Bonn at the end of the holiday in Norway. There were a whole series of boxes, he admitted, not just two, and he hadn't intended any deceit in getting Bauhaus to take one full of left-over souvenirs. I confess in my turn to having kept to Guillaume's first version of the story, for the same reasons as he first told it.

Wolf in his memoirs is rather disparaging about Guillaume and his vanity, and he confesses frankly that he sees the downfall of Brandt through his agent's actitivities as 'the greatest defeat we suffered up to that time . . . equivalent to kicking a football into our own goal'. This may go some way to accounting for another discrepancy between Guillaume's book and the later interview. In the book Guillaume speaks about Wolf with the greatest warmth and respect. In the interview his tone has grown much sharper. 'Herr Wolf,' he says, 'shouldn't say things today that were not so. Just because it doesn't suit him in retrospect to accept responsibility. He was very quick to excuse himself before God and the world.'

Guillaume's attitude to his other employer, too, has become a little more critical. In the book he speaks of him with nothing but admiration (and his attitude was remarked upon at the time by Bruhns and others). Now he says that Brandt was not always easy to work with. He would much rather have been personal assistant to Helmut Schmidt, whom he regards as the Federal Republic's greatest Chancellor.

I have in any case exercised a good deal of licence in other directions, though I think this is in most cases fairly obvious. The continuous contact that my Guillaume has with his controller is plainly a dramatisation of their discrete monthly meetings. The conversations that Guillaume has with Brandt on the train go much further in this direction. In his memoirs Guillaume says that Brandt became another man on his travels: 'Other cities, other faces, other thoughts, other problems - he discovered a new impetus towards them. Suddenly he seemed free and relaxed . . . He became talkative, excited by every good joke . . . En route he tanked up, and I made it my business to give him as much chance as possible to do it.' When there were no election trips in prospect, Guillaume invented the excuse of 'information journeys' instead. He alleges that on their travels together Brandt sometimes called him 'du' and he felt obliged to return the compliment. Nowhere, though, does he claim that Brandt ever carried this intimacy as far as conversations about his childhood or his personal feelings.