In January 2014, my 9-year old son, Finlay Marriott, died from a rare and inoperable form of brain tumour, Diffuse Intrinsic Pontine Glioma (DIPG). Through Finlay's Fighters, the group we set up in his honour, we have so far raised £100,000 to fund research, care and treatment via the DIPG charity Abbie's Army and The Royal Marsden Children's Unit. 

Although DIPG is, in Finlay's doctor's words "the worst possible tumour in the worst possible place", it gets less attention than it should as only 40 children each year are diagnosed in the UK. As a consequence, research into effective treatment is desperately underfunded. There is currently no hope for children with DIPG; the typical life expectancy from diagnosis is just 12 months.

Finlay's Fighters have done a huge amount over the past year to raise money and help make a difference. With your help we are getting there. In Finlay's memory, we are going to keep at it.

So, my good friend, Russell Fuller (BBC's Mr Tennis) has had the bright idea of running the London Marathon this year and has asked me to join him. Russell was diagnosed with testicular cancer in 1999, but made a full recovery - and will always be hugely grateful for the fundraising which brought about a major breakthrough in the treatment of the illness.

This time, running together, we will be raising money to help complete the build of the Francis Crick Institute in London's Kings Cross - a world leading centre of biomedical research and innovation.  It will house 1,200 leading scientists from a variety of disciplines working together under one roof to tackle the biggest challenges, giving us the best chance we can to find a cure for DIPG. 

Please support us in any way you can.