Both Dr Johan Byran and Dr Harriet Edwards have arthritis and will be raising funds for Arthritis Research UK. North London's Dr Byran is undertaking 12 marathons this year, travelling all over the world aiming to reach a £12,000 target. London junior doctor Dr Edwards said: 'Arthritis has had a huge impact on my life and I would like to help stop it doing the same to others.'
North London GP and former GP columnist Dr Mary Lowth is undertaking her first marathon - for Cancer Research UK. She said: 'In return for - hopefully - a fiver of your surgery profits, I would like to offer you my seven-point training plan, so that you too can spend your days exhausted and your nights aching.'
Suffolk GP trainer Dr Jenny Morrison is aiming to raise £1,800 for Age UK.
Also running her first London marathon is Bath GP Dr Sam Parsons. Originally from Cardiff, she is running for the Kidney Wales Foundation and said: 'I was keen to help support a local charity particularly as my aunt - who is a huge inspiration to me - receives dialysis and great support from the renal services at the University Hospital of Wales.'
Running his 22nd consecutive London marathon is east London GP Dr Stuart Bingham. He is raising money for Macmillan Cancer Support in memory of his brother who died of a retinal melanoma three years ago. He hopes to finish under four hours and his best time was three hours 26 minutes.
East Surrey GP Dr Joe McGilligan is raising money for Sense.
* Check out GPonline after the marathon to find out how the GPs did. Are you a GP competing? Email your detail to GP editor Neil Durham (email@example.com).