He is an acknowledged master of turning the air blue. But yesterday it was Gordon Ramsay on the receiving end of an expletive-laden rant.

His most famous protege - and former close friend - Marcus Wareing yesterday described him as a 'sad b*****d' whose influence had left him feeling 'trapped and constrained'.

It was a surprising outburst given the men's successful 25-year working relationship, and the 15 Michelin stars they have won between them.

Ramsay, 41, was even the best man at his former friend's wedding.

Happier times: Marcus Wareing and Gordon Ramsay after they received the AA Restaurant of the Year Award for the restaurant Petrus

Wareing's comments follow a bitter legal battle over his position running Ramsay's two-star restaurant Petrus at the Berkeley Hotel in Knightsbridge, West London.

He has spent nine years heading up the kitchen, but in May the hotel announced it wanted to work directly with him, rather than deal with Ramsay's company. The move has been challenged by Ramsay's lawyers.

Michelin-starred chef Marcus Wareing has hit out at his former boss

Wareing now claims he would rather 'kill myself' than work with his mentor again.

'If I never speak to that guy again for the rest of my life, it wouldn't bother me one bit,' he said. 'Wouldn't give a f***. I admire Gordon. But would I lose sleep knowing he

wouldn't be there? No chance. When you wake up in the morning and look in the mirror and all you see is a man who is constrained, confined and trapped, then you've got to change.'

The relationship between the men dates back to 1993, when Ramsay invited Wareing to work for him in the kitchens at Aubergine.

But the younger chef, now 38, says he is determined to prove himself by matching the three Michelin stars held by his mentor at his Royal Hospital Road restaurant in Chelsea.

'Gordon loves being the only three-star here,' he told Waitrose Food Illustrated. 'He's milked it for years.

'I don't want to get to the end of my career and say that I never really achieved what I wanted to because I felt restrained.

'If he wants me never to get to the status I want, then my advice to him is: put a gun to my head, shoot me, put me in a box and bury me because if you don't I'll come back and I'll come back. I'll never give up.'

Ramsay's spokesman yesterday declined to comment.