A senior manager working for hairdresser-to-the-stars Trevor Sorbie threatened to expose her boss's private life after her request to work part-time was refused, a tribunal heard.

Jasmin Gupta, from Brighton, also demanded £200,000 when told working two and a half days a week would not be possible.

The tribunal, sitting in central London, heard evidence this week that Mr Sorbie asked a member of staff to supply him with cannabis.

Ms Gupta is claiming unfair dismissal and sex discrimination against Trevor Sorbie International.

Her colleague Carol Stephens, in charge of Mr Sorbie's hair product range, told the tribunal she had a meeting with Ms Gupta and the company's managing director Grant Peet.

She said Ms Gupta, a commercial director, was finding it difficult to work with Mr Sorbie.

She told the hearing: "She said I want to go part-time or I'll have to leave the company'."

Miss Stephens said Mr Peet told the commercial director at the meeting last July she would have to leave the company because if she went part-time she would still be working with Mr Sorbie and could not do her allotted hours in two and a half days.

Miss Stephens said Ms Gupta looked angry.

She said Ms Gupta said: "I want £200,000, there are things I know about Trevor's private life I'm sure you don't want to come out."

Miss Stephens said her colleague felt Ms Gupta's comments were a threat.

Mr Sorbie's customers have included Chris Tarrant, Lesley Ash, Denise Van Outen, Natasha Kaplinsky, Julian Clary, Lesley Garrett - and the Queen.

He opened a salon in The Lanes in Brighton two years ago.

The tribunal heard that Ms Gupta, real name Julia but known by her professional name of Jasmin, joined the company as a trainee hairdresser more than 12 years ago and rose through the ranks to become the commercial director, earning more than £110,000 a year.

In a written statement to the hearing, she said: "From February 2005 I was aware Trevor Sorbie often smoked marijuana at work and on shows and asked staff to supply him with drugs.

"I also experienced crisis, temper tantrums and a mental breakdown from Trevor Sorbie."

Ms Gupta said she understood she was in a well-paid job which could put her under stress but the pressure became "totally unacceptable and unmanageable from January last year".

Mr Sorbie in his written statement admitted he smoked cannabis from "time to time" but denied he had a drinking problem.

The hearing was told both party's lawyers would make submissions to the panel next month who would deliberate on the proceedings at the end of August.