Go on then!
My friend's fella ran it last year and at the end, in Horseguards parade, he looked shattered and could barely move. He was still adamant he was coming down the pub for a few though! What surprised me, as a spectator, was the number of Saints shirts in the watching crowd. (Besides mine.) If I CAN make it this year, I'll be wearing the sash, and usually stand around the Canary Wharf bit.