Hope from tragedy: Runner who died in marathon raises more than £300,000 for charity

She set out with £400 pledged to Samaritans. Now donations have reached six figures

“I'm running the London Marathon for Samaritans because they continuously support others.” That was Claire Squires's rallying call for donations before she embarked on the race on Sunday morning, when she had accumulated just over £400.

This morning, with her friends still trying to come to terms with the sudden death of the 30-year-old hairdresser, who collapsed moments from the finishing line and could not be revived, donations on her JustGiving.com fundraising page had exceeded £300,000.

Tributes poured in from around the world as people visited her web page to pay respects and leave donations – many of them for £5 or £10. There are now more than 27,000 donors.

One among them, Paul Garbett, wrote: "I have never met Claire, but her commitment to do something amazing for charity speaks volumes about the type of woman she was."

Ms Squires, from North Kilworth, Leicestershire, had run the marathon once before and was in apparent good health before she collapsed at Birdcage Walk, near St James's Park, on the final stretch of the 26.2-mile race. Immediate medical attention was provided but paramedics were unable to revive her.

Post-mortem tests over the coming days will try to establish the cause of her death, which has once again raised the issue of the safety of marathon running. Ms Squires is the 11th participant to die since the event was founded in 1981, and the first woman. Five of the previous fatalities in the London Marathon were caused by heart conditions of which the runners were unaware.

Yesterday friends described her as an "inspiration" who brought laughter and love to everyone's life. Nicola Short, who climbed Mount Kilimanjaro with her two years ago, said: "She was an inspiration to us all and will be sorely missed." Lillie Renshaw-Booth wrote: "Thoughts with you. Can't believe it. She was so healthy."

Catherine Johnstone, chief executive of Samaritans, said the organisation was deeply saddened at the news. "We are devastated following the tragic death of one of our marathon runners and are supporting the family through this very difficult time.

"We appreciate all that our marathon runners do. It is with their support, commitment and fundraising efforts that that we are able to offer our vital service for people with nowhere else to turn."

Professor Sanjay Sharma, medical director for The Virgin London Marathon, told the BBC yesterday: "Her death is likely to be due to a heart problem. I was there at the arrest and was deeply shaken. To see a 30-year-old who is amazingly athletic die is so counterintuitive. These deaths are rare."