Vale MP, Alun Cairns, is set to take part in his 12th marathon, having already raised more than £100,000 for charities in his previous races.
His son Henri Cairns will accompany him on the 26.2-mile course, making his first attempt at the gruelling challenge.
Mr Cairns, fast becoming a dab hand at marathons, currently holds the record as the fastest MP amongst current members of the Commons and Lords, with a time of three hours and twenty-eight minutes, but is almost an hour behind former MP Mathew Paris.
This year will see him running in support of Children with Cancer, a charity that spearheaded a ground-breaking clinical trial resulting in a significant advance in childhood leukaemia treatment.
Mr Cairns said: “Children with Cancer do fantastic work and it is a privilege to support such a good cause.
“They help fund research and support children diagnosed with cancer and help their families cope.”
If you wish to support Children with Cancer, you can pledge by sponsoring Alun and Henri via the London Marathon’s website.