'So I called her dumb, blonde and decorative? That's not an insult'

Joking about dumb blondes, topless women and sex is a perfectly reasonable way to behave at work, a wealthy financier has insisted.

In Mark Lowe's high-octane world of hedge-fund management, risqué comments and e-mails about women, lady-boys and sheep are just part of the wallpaper.

"None of the jokes were demeaning or provocative," he said yesterday as he defended himself against a £4m sexual discrimination claim by Jordan Wimmer, an executive he called a "dumb blonde" and "decorative".

A selection of the jokes he shared with colleagues at investment firm Nomos Capital was read out to the Central London Employment Tribunal, including one in which women were described as "hazardous material" found in various grades "from virgin to common ore" that "react well to gold and precious stones".

Then there was the one about a Ferrari being cheaper to run than a woman, a message titled "An engineer's guide to women" and a sexual encounter described using road signs. One joke asked: "Who is your real friend? Put your dog and your girlfriend in the rear boot of your car for an hour and see who still likes you when you open it." Another e-mail featured a photo of a sign that read: "Men: no shirt, no service. Women: no shirt, free drinks."

Mr Lowe, who has built up a £100m fortune, said he was unable to understand how anyone might be offended by such e-mails. "I thought they were funny. They weren't brilliantly funny, but they amused me," he said. "It shows I found a joke funny and circulated it to the rest of the team. I didn't think there was any question of appropriateness at all. It's an amusing joke, the team were all adults."

Ms Wimmer, however, thought otherwise and has taken Mr Lowe to the tribunal after claiming sex discrimination, unlawful deduction of wages, unfair constructive dismissal and disability discrimination.

Julian Wilson, representing Miss Wimmer, 29, questioned the hedge-fund boss's sensitivity towards his employee. She had, the tribunal heard, expressed her discomfort at dumb-blonde jokes.

However, after returning to work following treatment for depression, she was confronted by an e-mail entitled the "great dumb blonde joke" in which a woman was "mentally incapable" of distinguishing between a packet of cornflakes and a jigsaw puzzle.

Mr Lowe told the all-female panel: "I didn't for a moment suppose anyone would take exception to a feeble joke of this sort. It was not directed against [Ms Wimmer]. The thought never occurred to me that she'd be offended."

Mr Wilson suggested in cross-examination that the jokes indicated the nature of the hedge-fund boss's view of women and that it revealed he thought it "appropriate to bring sex references into the workplace". He told Mr Lowe: "It explains something of your own view, that's why you find these jokes amusing. You did regard woman as decorative objects, didn't you?"

Miss Wimmer, 29, a Canadian living in west London, started working for Mr Lowe at Nomos Capital in 2004, where her annual salary quickly rose from £50,000 to £577,000. She left in February this year.

She has made a string of allegations against Mr Lowe in her discrimination claim, including that he would bring escort girls – Natalia Malagina and a woman known only as Ling – into board meetings while dressed provocatively. Ms Wimmer said she found this humiliating.

The 59-year-old boss, who now lives in Switzerland and is the only shareholder of Nomos, denied the allegations and told the hearing the women were both his girlfriends, though now they are just friends. He said Ms Malagina, who once worked as a stripper and escort, was interested in the hedge- fund industry, and he sponsored her while she undertook an internship in New York. He denied he paid her money "for favours".

Earlier in yesterday's hearing, under questioning by his own counsel, Elizabeth Melville, Mr Lowe categorically denied allegations made by his former employee that he had hired a hitman to kill her. The hearing continues.