But Ronnie O'Sullivan and John Higgins are rated as close challengers for the tournament, which starts at the Wembley Conference Centre on Sunday.

Williams, who won the title in 1998, beating Stephen Hendry on a respotted black in the deciding frame, is quoted at 10-3 by official bookmakers William Hill.

O'Sullivan, who has already picked up three titles this season, is 7-2 joint second favourite along with Higgins.

Scottish legend Stephen Hendry, who spoke out on Wednesday in support of a tobacco- free sponsored circuit planned for next season by The Sportsmasters Network, is 11-2.

Defending champion Matthew Stevens, struggling to find his form in recent matches, is 14-1 to retain his title.

Irish ace Ken Doherty, runner-up in the last two Benson and Hedges Masters finals and a winner last Sunday of the Welsh Open in Cardiff, is quoted at 11-1.

The Masters, now in its 27th year, takes place at Wembley from 4-11 February.

The total prize money stands at a record �650,000, with the winner collecting �175,000.

The tournament hosts the world's top 16 players, together with two wild card entrants.

Teenager Shaun Murphy, who is only 19, qualified by winning the Benson and Hedges Championship at Malvern last November when he was ranked 150 in the world.

Jimmy White, who received the sponsors' invitation, will bring his army of fans to what he calls his local tournament. The Whirlwind's odds are 50-1.