Karin wondered if she was joking, but it was obvious from her manner she was serious.

“We British like to give the impression of being bumbling amateurs, but some of us aren’t that easily fooled, and although it made an exciting story for the press, your escape from East Berlin was just a little too convenient.”

Karin felt herself shaking.

“If the Labour Party were to win the next election, you would be well placed to cause considerable embarrassment, not only for the government, but for this country.”

Karin gripped the arms of her chair.

“We’ve known for some time that John Pengelly isn’t your father, and that he reports directly to Marshal Koshevoi. But what puzzles us is that although you’ve been living in this country for more than two years, you don’t appear to have passed any information of real significance to the other side.”

Karin wished Giles would come and rescue her, but she knew there was no chance of that.

“I’m relieved you’re not foolish enough to deny it, because there is a way out of this mess, as long as you’re willing to cooperate.”

Karin said nothing.

“I’m going to give you the chance to work for this country. I will personally make sure that you are regularly supplied with information that will keep the Stasi convinced you’re still working for them. But in return we will expect to know everything Pengelly is up to, and I mean everything.”

Karin picked up her cup but her hand was trembling so much she put it straight back down.

“I will be your handler,” the baroness continued, “and what better cover could you have than the occasional tea with a silly old bat from the House of Lords? That’s the story you’ll tell Giles, unless you want him to find out the truth.”

“No, that’s the last thing I want,” stammered Karin.

“Then let’s keep it that way. My husband, dear man, went to his grave thinking I was an undersecretary at the FCO, which indeed I was, to all intents and purposes. He would have burst out laughing if you’d suggested I was a spy. I should warn you, Miss Brandt, that if you feel unable to go along with our plan, you will be on the next flight back to East Berlin, and I will be the one who has to tell Lord Barrington the truth.” She paused. “I see you have some feeling for Giles.”

“I adore him,” said Karin without guile.