An employee of JP Morgan pretended to be a Mossad agent as part of a ploy to win back his former girlfriend and colleague.

The year-long affair between US bankers Daniela Rausnitz and David Gray, who was married at the time, came to a head yesterday at West London Magistrates' court. Mr Gray, 28, was convicted of harassing her after the couple broke up.

Ms Rausnitz, 25, moved to London to escape her stalker. But he continued to contact her, inundating her with calls, text messages and emails, and developed elaborate stories to convince her to see him, including pretending that he had a serious illness. At one point he stole a set of candlesticks from her flat.

Mr Gray was captured by police when he arrived at the Park Lane Hotel, where Ms Rausnitz was hiding. He tried to convince police officers that he was there because he was with the Israeli secret service.

"His erratic and obsessive behaviour began to frighten me and I was hopeful that moving to London would put an end to it," Ms Rausnitz said. "Unfortunately it escalated. His unwarranted, unprovoked and unrelenting actions have caused me extreme distress."

Dan O'Callaghan, Mr Gray's lawyer, said his client was a "pathetic lovelorn fool".

Mr Gray is understood still to be employed by JP Morgan, but the bank declined to comment on the case.