I'm running the London Marathon in aid of Great Ormond Street's Face Value appeal to help kids like my nephew Oscar who suffer from Crouzon syndrome.

Crouzon syndrome is a rare genetic condition that causes the craniofacial bones to fuse prematurely. Oscar has already had numerous operations to relieve pressure on his brain and eyes and to improve his breathing. When Oscar is holder he'll need another major operation at GOSH to help reshape his skull so that his brain can keep growing.

The Face Value campaign was set up by my family to help raise £1 million in order to develop life-changing new techniques to help children like Oscar.

We have so far raised £800,000. Any support you can give will be hugely appreciated.

Piers