On Sunday 25 March I'll be running the London Landmarks half marathon for Mencap - just 2 days before my 40th birthday, which, according to my brother, is when I will officially become an old man.

I haven't let that put me off though!

I have been pounding the streets of South London in the sun, rain and, most recently, snow, with the hope that I won't completely embarrass myself over the 13 miles. 

It looks set to be a fun day, with the route taking in the big sites like Buckingham Palace, St Paul's, the Shard and other tall pointy buildings!

My decision to raise money to Mencap is a no-brainer really. I work for Mencap for starters and so have seen first-hand the good that the organisation is making to people's lives. 

I am lucky enough to be at the heart of a lot of our efforts to campaign and lobby (I'm the Parliamentary Manager) to improve things for people with a learning disability and their families. This might be trying to improve support for children with special educational needs in schools, or fighting disability benefit and social care cuts.

We don't get a penny from the Government towards our lobbying and campaigning efforts and that's why fundraising is so important to us. 

Our newest campaign is called Treat me well and is about getting doctors, nurses and the Government to understand how to better treat people with a learning disability in hospital.

Tragically, we know that 1,200 people with learning disability die each year because they don't get the healthcare they need, and this needs to change.

Campaigns like this can make a real difference and that's why I thought it was more than justified to fleece my family and friends for some dosh!

I have a fundraising target of £1,000, but I am not quite there yet.