Donations pledged in memory of an Army captain who died in Sunday's London Marathon have reached more than £130,000.

David Seath, a 31-year-old fire support team commander in the Royal Artillery, had a suspected cardiac arrest three miles from the finishing line. The exact cause of death is yet to be established.

He had hoped to raise £250 for the Help for Heroes charity and had written on his Just Giving page to thank his supporters the day before the race: "A big thank you to everyone that has been so generous... to have broken the £200 mark with your help is very special."

Donations have since reached more than £54,000, more than 200 times his original target.

His friends have also raised more than £76,000 for the charity on a second fundraising page and plan to "complete what he started" in Seath's honour.

"We will walk as one, the final three miles of the marathon, starting where he fell," said Capt James Walker-McClimens, who went on tour in Afghanistan at the same time as Seath.

He told the BBC: "He was the greatest type of guy you could imagine – everyone loved him. He was funny, outgoing, generous – he was just not a bad guy in any way shape or form.

"In the Army, we don't like unfinished business. It was something he wanted to do; he wanted to do the full marathon, so we are going to complete it for him."

A minute's applause will also be held during the Army v Navy rugby match at Twickenham on Saturday, 23 minutes into the game.

Help for Heroes offers support to those who have suffered life-changing injuries and illnesses in the line of duty.