He promised beforehand to save his best for the day – and courageous Craig Richardson did just that today as he completed the London Marathon.

The 25-year-old former RAF Regiment senior aircraftman from Dereham, who lost half his leg in an explosion in Afghanistan in 2008, ran the race of his life wearing his carbon-fibre blade, tailor-made for running.

He crossed the finishing line with a time of around 5 hours, 46 minutes and won the respect of thousand upon thousand of fellow athletes and spectators.

There was no gain without pain as he neared the finish struggling with Achilles tendon trouble and as the impact on the stump of his right leg took their toll. 'I was limping, and in a bit of pain,' he conceded.

But, after his terrible injury, did he ever think he would be lining up - let alone finishing - a marathon distance? 'Never. I honestly would not have believed it,' he said tonight.

Craig shrugged off pre-race nerves and put aside the 'everyday' prosthetic limb he uses the rest of the time to join the 37,500 field in the 32nd London Marathon.

He also forgot the suffering during training and socket problems he had experienced with his blade in post-Christmas preparations. Before leaving Dereham for London, he said he hoped he was saving his best for the day.

In fairly warm and eventually damp conditions, the going began to get tough for Craig after 12 to 15 miles. But he was buoyed by the atmosphere and good wishes of the crowd and runners.

'The whole thing was amazing,' he said. 'People looked at my leg and then looked at me and it was really nice because people I didn't know were saying to me: 'Well done,'' he said.

Cheering him on too, and catching a glimpse of him at various stages among the melee, was a contingent of family and friends including his mum Ann, brother Jamie and sister Paige.

Also among them was Paul Sandford, landlord of the Railway Tavern in Dereham and owner of the Joint Effort gym at Wells, where Craig did some of his weeks and weeks of training. He organised a minibus to take them to London.

'Seeing my family and the others was one of the best things,' he said. 'It was great having them there - it gave me a real boost.'

Before he set off yesterday, Craig already reckoned to have raised between �1,000 and �1,500 as his contribution to the Norwich Community Sports Foundation team effort, He hopes that sum will swell to �2,000.

Craig was on patrol in Kandahar in October 2008 when he lost his right leg below the knee. He underwent intensive rehabilitation at the Headley Court defence medical rehabilitation centre in Surrey and was medically discharged from the RAF last year.

But he has inspired countless people in his home town, across Norfolk and beyond with his determination to complete the marathon against all odds. Today, he did just that. And now another marathon? 'You never know. I'm crazy enough to do it,' he said.

You can still pledge support to Craig at uk.virginmoneygiving.com/CraigRichardson