The Prime Minister's press secretary Alastair Campbell has raised more than £200,000 for the Leukaemia Research Fund so far, taking him into the top 20 individual London Marathon fundraisers.
Among his sponsors, listed at www.justgiving.com, are former Tory leader William Hague, home secretary David Blunkett and former Labour leader Neil Kinnock.
However, it is the comments left by sponsors that make interesting reading.
Former ITN political editor John Sergeant said: "It's great to have got you on the run", while another friend Gordon Campbell, said: "Don't let the gits at the Daily Mail get you down."
One name conspicuous by its absence from the online list is the prime minister Tony Blair, who may, however, have pledged his support offline.