'The mistake every winner makes is to think their book is genuinely the best'

Writers, publishers and the rest of the literary beau monde dined alongside 300 "suits" from the corporate world last night to inaugurate a new era for Britain's most prestigious book prize.

The guest list in the Great Court of the British Museum, in the shadow of the British Library Reading Room, illustrated how the Booker Prize had firmly embraced big business.

The award is now the Man Booker, thanks to the Canadian financial services business which has invested £2.5m over five years to claim ownership of the prize that was won last night, appropriately enough, by a Canadian, Yann Martel, 39.

The deal explained why the winner's cheque was £20,000 bigger than the £30,000 that Peter Carey walked away with last year for True History of Kelly Gang.

It was why the dinner was bigger too, as 200 people from Man Group saw off 100 people from the Big Food Group, the company that owns Booker, who were presumably on their swansong literary jolly.

And the staid environs of Guildhall in the City were swapped for the glamour of drinks in the Egyptian Room of the British Museum followed by dinner in the imposing Great Court next to that iconic Reading Room.

The recognisable faces, however, appeared largely the same. David Baddiel, a guest in previous years, was there to judge it. Tessa Blackstone, the Arts Minister, was there, alongside Ian Hislop, of Private Eye, and Joan Bakewell, a grandee of the cultural circuit. Young writers such as Alain de Boton rubbed shoulders with former winners such as Ben Okri, resplendent in a gorgeous waistcoat, and Bernice Rubens, winner of the second prize in 1970. But at least Beryl Bainbridge, in previous years often the bridesmaid at literary awards but never the bride, had no anxious wait last night.

This year it was the turn of Yann Martel, Rohinton Mistry, William Trevor, Sarah Waters and Tim Winton to wait. Carol Shields, sadly, was too ill with cancer to attend.

Martel, one of three Canadians on the list and the third Canadian to win (after Michael Ondaatje and Margaret Atwood), spent the wait for the announcement of who had won sober but thrilled.

"I am ecstatic to be here,'' he said, oblivious at the time of his impending wealth. "It's a great location. It's not the real world, but a little escapism is nice.''

Thanks to the moment last week when the prize website inadvertently suggested that he had won, Martel had become the bookies' favourite and had many supporters in the room.

Bernice Rubens, who was told in advance when she won, thought he was the likely victor but clearly hoped that the Irish-born writer William Trevor, now 74 and living in Devon, would pull off his first Booker success.

"If the prize was given to someone for a body of work, he would win,'' she said. But, she added over the lamb confit from the chef Gordon Ramsay and a decent red wine, "the most important thing with Booker is not to take it too seriously. I've judged it too, and it's entirely on the tastes of the jury.'' She thought every winner made the mistake of genuinely believing their book was the best of the year.

After he was officially named the winner, Martel, the Spanish-born son of diplomats, said: "I feel like I'm in the arms of a beautiful woman. This is a writer's dream, to win such a prestigious prize as the Booker. It feels like winning the Lottery.''

Having money was going to be a new experience, he said. "I've always been a poor writer. I've never owned anything, not even a car. Perhaps I'll find a green investor for the money and then go to better restaurants and travel more.''

The fatter cheque was certainly likely to change his life for the better. But it did not please the Booker purists, many of whom could be seen muttering in corners about the burgeoning corporatism of their favourite prize.