Andy Murray has stunned the tennis world by sacking his coach Brad Gilbert after a successful 16 months together that saw the Scotsman's ranking rise from 36 to a high of eighth. One bookmaker has reacted by opening a book on what the split will do to his World ranking.

Murry missed three months of this year through injury, yet was still just one victory from securing a place in the Masters Cup in Shanghai for the world's best eight players.

Murray said: "Despite being injured for almost four months this year, I am pleased with my 2007 results and am very grateful for the help that the LTA have given me by providing Brad Gilbert as a coach."

Part of the problem appears to be that Murray needs a team around him as he travels the world. Murray, 20, admitted that travelling with just one coach was sometimes "stressful".

"I'm the sort of guy who likes a lot of people around me. Sometimes when it's just one-on-one with the coach, it can get quite stressful and a little bit stale. It's just much more fun travelling around the world because it can get quite lonely sometimes and to have a lot of people around you just makes you feel a little bit more at home, when you're away." 

William Hill have opened a book on the British No 1's final world ranking in 2008 and make between seventh and tenth their 6/5 favourite offering and 2/1 that he falls out of the world top ten. For those who fancy a tennis bet, Murray is 7/1 to win a Grand Slam in 2008, 7/1 to be BBC Sports Personality 2008 and 20/1 to win Wimbledon.

"As far as we are concerned Andy Murray is the real deal and even without Brad at the helm, we expect him to have a good year in 2008," said William Hill spokesman Rupert Adams.

William Hill odds:

7/1 Andy Murray to win a grand slam 2008; 7/1 A Murray 2008 Sports Personality of the year

What will Andy Murray's 2008 year end official ATP entry ranking be?: 6/5 Between seven and ten, 2/1 one to six, 2/1 eleven or worse

To win a major: 20/1 Wimbledon, 25/1 US Open, 25/1 Australian, 50/1 French