22 Aug, 16:30
Fans can soon purchase tickets for Rugby World Cup 2015, when they go on sale to the general public from September 12 - 29.
The race, in its third year, is run by teams of 12 with each participant running five times, with three team legs and two individual legs. Legs vary between three miles and 13 miles, with an average of six miles.
Organiser Nicky Pinnell said: "This is the only event I know of where, halfway through, teams are helping each other out, pulling over to send another team's runner back on track, as they had missed a turning.
"People from different teams run in pairs with someone they met only hours before. It becomes about getting everyone to the finish and not about beating one another.
"Last year we raised more than £20,000 for charity and this year we hope to raise even more."
The closing date to apply is Saturday, March 31. To find out how to sign up, visit londoncardiff24.co.uk.