Mon Mome, the 100-1 winner of the 2009 Grand National, has been retired.

The 13-year-old has not won since he triumphed by 12 lengths at Aintree four years ago, and trainer Venetia Williams has admitted that the horse's lack of form was a factor when considering his retirement.

Williams told the Racing Post: "He's been an amazing horse to train and gave me the best day of my career when winning the Grand National.

"He showed a bit of form at Wincanton earlier this year, but has not run anything like that since and we've decided to retire him, as that was going to be the plan at the end of this season anyway."

The French-bred horse recorded six victories from his 53 races.