With the London Marathon back once again, a number of celebrities have taken the challenge to beat the gruelling 26.2 mile stretch across the capital - with some pretty impressive results. Just finishing a marathon at all is an incredible achievement, and these celebs can be proud of their fantastic efforts on the day - whether they are experienced runners or attempting the race for the first time.The mass participation section of the race started at 9.40am on Sunday, with the celebrities being joined by tens of thousands of people all looking to beat their personal bests, raise money for charity, or take on the challenge of a marathon.