St Neots charity runner Iain Holiday has described the London Marathon as the “hardest marathon” he has ever done but is on course to complete his fund-raising challenge this weekend.

London was his third marathon in three weeks and this Sunday he will take part in an event in Hamburg to raise money for Cancer Research UK.

Iain, from Howitts Gardens, in Eynesbury, ran in Manchester on April 8, Brighton on April 15, London on April 22.

Sunday's event in London caused problems for many runners due to the high temperature on the day and that and some niggling injuries saw Iain record his slowest ever time.

"That was the hardest marathon I have ever done," he said.

"I have never walked in a race before, and I started walking from mile 18. I hit the wall even earlier at mile 11. Mentally I went with the wrong plan and it showed, I have never felt so tired, sore and drained. The 18-hour day of removing and re-fitting a gearbox on the Saturday didn't help. My glute pinged but I managed to keep that pain away. I crossed the finishing line running with my slowest ever time of 3:59. I am a little dishearten due to my competitive nature but looking forward to Hamburg and putting everything in to completing it in under 3:20.

Iain, a project manager, decided to raise money and awareness for the charity after his partner, Helen West, was diagnosed with breast cancer in February last year at the age of 25. Helen was treated with chemotherapy and has been part of a cancer treatment trial at Addenbrooke's Hospital, in Cambridge. She also underwent a double mastectomy after tests showed she was a carrier for the BRCa gene. The BRCA1 and BRCA2 genes greatly increase a woman's chance of developing breast and ovarian cancer. Researchers have recently identified more than 100 new gene variants associated with an increased risk of breast, prostate and ovarian cancer.

INFO: If you would like to support Iain's fund-raising effort, go to: www.virginmoneygiving.com/iainholiday.