Wallington-based David Weir's sprint finish proved decisive again when he completed a hat-trick of London Wheel-chair marathon wins on Sunday.

It was nip and tuck all the way round the 26-mile 385-yard course as Weir and six of his rivals, including world record-holder Hans Frei from Switzerland, slugged it out.

There were never more than inches in one of the most exciting contests in the history of the London wheelchair race.

As they passed Buckingham Palace, within sight of the finish in the Mall, seven racers were still in contention.

In the last few hundred yards, Weir's explosion of speed saw him edge ahead to cross the line in one hour 33 minutes 56 seconds.

That was four seconds ahead of Australian Kurt Fearnley, followed by Frenchman Denis Lemeunier (1:34:01), South African Krige Schabort (1:34:02) and Frei (1:34:03).

South African Ernst Van Dyk and American Joshua George collided 100m from the finish and crashed into the hoardings of the spectators' stand, but entangled themselves to finish sixth and seventh.

Weir's fourth London victory provided the biggest cash day of his career as he lifted £7,600 in prize money.

"I knew it would be tough and I tried to break away a few times," said Weir, 28.

"I tried to use the hills to my advantage, but the headwind was too strong.

"I know I have got a good sprint finish so I just stayed with them and got them all at the end.

"I was harder than last year. It was very tactical and there was a bigger pack all the way."

Asked about the secret of his success at London, Weir revealed: "I train in Richmond Park with are a lot of hills and flat roads where I am able to get up speed very quickly."

After warm weather training in Portugal, Weir will compete over 400m and 1500m at next month's Paralympic World Cup in Manchester.

Sunday's win earned him qualification to represent Britain in the marathon at this summer's Paralympic Games in Beijing.

Weir will also compete on the track there, but apart from the marathon is keeping his intentions secret.

He will compete in an exhibition race at the Olympic Stadium in Beijing a few weeks before the Games open.

Weir, forced to miss last year's World Championships in Osaka with glandular fever, maintained the good form he showed in winning the Lisbon half-marathon - eight seconds outside the world record.

However, his agent Karen Berkley admitted Weir nearly pulled out of Sunday's race because he had been feeling unwell for several weeks.