Robert O'Brien will complete the gruelling 26.2 mile race on behalf of the charity Cardiac Risk in the Young - CRY. 

His childhood friend Tim Daines, a fellow pupil at Bishop Luffa School, died of a suspected cardiac problem while playing football in April last year.

Although accurate statistics are not available, experts estimate that between four to eight young people in the UK die suddenly of cardiac abnormalities.

The majority of these sudden deaths are due to inherited forms of heart muscle disorder and irregular heartbeat.

Robert said:" Tim was fit as a fiddle, clean living and didn't smoke.

"The last time I saw him was at my house before he went to play football.

"A few years before Tim passed out while playing football.  He went to the doctor and had a check up, but he should have had an ECG test while on a treadmill.

"There's a chance Tim's death could have been prevented if he'd been screened.  He may have had to change his lifestyle but he could still be alive today."

Robert will don CRY's trademark heart costume for the marathon on 13th April.