Microsoft's former UK enterprise partner director and board member Simon Negus is suing the software giant for wrongful dismissal months after it slapped a writ on him to repay part of a bonus and holiday money.

He left the firm last September amid allegations of inappropriate behaviour and was the subject of a lawsuit filed by the firm in April when it tried to recoup £75,000 of the £225,000 signing-on fee it paid when Negus joined from Dell in 2008 on the condition that he stay for three years.

Negus denied allegedly planting a smacker on a workmate at WPC in Atlanta in 2009 in full view of attendees, but when additional information came to light he was dismissed, Microsoft said in its claim, quoted in a report by Bloomberg.

An internal investigation by Microsoft found he had "behaved dishonestly, and thereby acted in a manner calculated or likely to destroy trust and confidence between him and Microsoft," the court filing states.

The case brought by Negus, now COO at Upstream Systems, was filed on 3 August for wrongful dismissal, breach of trust and harassment.

Negus declined to comment and Microsoft had no-one available for comment at the time of going to press. ®