'Willy Wonka' resigns after his meltdown at the chocolate counter

In the competitive world of high-end chocolate products, few men enjoyed the stellar reputation of Barry Colenso, Thorntons' master chocolatier.

A former chief patissier at the Savoy Hotel, Mr Colenso had designed cakes for the Queen and Prince Charles. He took his position at Thorntons 20 years ago, and this year became the man behind the world's first chocolate billboard when it was unveiled in Covent Garden last Easter. It was a publicity coup that further cemented his reputation as the "Willy Wonka" of the British chocolate industry.

So when staff from a rival company witnessed Mr Colenso performing a wanton act of sabotage on a collection of their best truffles, they could scarcely believe what they saw. The master chocolatier was caught on CCTV ruining chocolates worth £63.50 at the Hotel Chocolat store in Nottingham. Staff said he was observed "handling truffles in a suspicious manner".

A quick check after he had left revealed a trail of destruction across the glass unit of the display counter as truffle after truffle had been mercilessly squashed under thumb. "This was an extraordinary act of truffle-squishing. We can only guess at what provoked it," said a Hotel Chocolat spokesman: "The staff observed Mr Colenso handling a number of truffles in a way that made them suspicious. When we checked the truffles, they had been squashed and damaged."

Mr Colenso has now been forced to resign in disgrace. A Thorntons spokesman confirmed: "Mr Barry Colenso has resigned. We will not be commenting any further on this matter."

In what must have been a humiliating exchange, Thorntons were forced to admit to their arch rival's that Mr Colenso had indeed "handled the truffles".

Thorntons, launched in 1911 by Joseph Thornton in Sheffield, has remained almost unchallenged as specialist high street chocolatiers with more than 500 stores across the UK.

But Hotel Chocolat is seen by many as a possible pretender to Thorntons' crown as the ubiquitous chocolate shop. The firm launched 14 years ago as a catalogue service and opened its first store in 2004. It now has 23 stores, and is growing apace with four more set to open in the coming months. Peter Thornton, former chairman of Thorntons and grandson of the founder, said: "Obviously this man must have been under a tremendous amount of pressure to do something like this, quite extraordinary behaviour.

"I believe Hotel Chocolat does represent the first real challenge to the company. Thorntons have allowed them to come into a position in the market where they should have been: the aspirational, lifestyle area. Thorntons has become more of a chocolate shop over a chocolate specialist these days. It's disappointing."

Mr Colenso's chocolate billboard attracted national headlines as children across the capital helped devour the 390kg (860lb) of chocolate bunnies and eggs in less than five hours with the proud creator giving interviews to the assembled press.

Mr Colenso, a father of three, who lives in a luxury home in Belper, Derbyshire, said recently: "My job is to turn the dreams of myself and my colleagues into a chocolate."

Mark Demarquette, chocolatier and owner of the Demarquette chocolate shop in Chelsea, west London, said top chocolatiers were under the same types of pressure as Michelin-starred chefs. "Mr Colenso's behaviour is very surprising, something you'd really expect from the continent. Thorntons went through a trough recently and Hotel Chocolat stepped in. But things are looking better for Thorntons again.

"But no one likes competition when you've got a monopoly. It means you've suddenly got to pick up your game. The pressure is constantly on you to deliver as a chocolatier and when you are making massive batches like Thorntons, you can end up having to throw away tonnes of chocolate if you get it wrong.

"I imagine Mr Colenso was getting it from all sides, including the board of directors," he added. "I'm sorry to report that the life of a chocolatier is not a bit like Willy Wonka's. Sometimes I wish it was. It would great fun."