Donations made through online sponsorship for this year's Flora London marathon have already doubled last year's internet total.
With more than two weeks to go until race day on 13 April, charity runners have raised more than £500,000, easily beating last year's total of £200,000.
The online donation facilities, which are provided by official marathon partner Justgiving, have proved popular.
An extra 300 charities registered in preparation for the marathon, and 3,200 runners are using the service. They can set up a web page to collect credit and debit card donations so they don't have to prompt sponsors for cheques or cash. Charities benefit because they don't have to chase the runners and Gift Aid applications are automatically made for them.
The Leukaemia Research Fund, whose team of runners includes the Prime Minister's press secretary Alastair Campbell, has found the facilities helpful. "There is a charge for using the service, but compared to the administrative costs of processing donations and Gift Aid applications ourselves, it is very cost effective," said Cathy Gilman, campaigns manager at the charity.
The donation service will stay open until 13 June, and donations are expected to continue flooding in. "I wouldn't like to predict an ultimate total, but we have seen an increase in donations of roughly 600 per cent on this date last year," said James Grieve, spokesperson at Justgiving.