With months of hard training behind them, 36,500 runners are counting down the hours until the London Marathon.
Celebrities, fun runners and elite athletes are all hoping to avoid any last-minute pulled muscles or strains as they get ready for the 30th anniversary race.
Many of the runners are fully-fit men and women raising cash to help people overcome sickness and disability.
But Pc David Rathband, who was blinded by gunman Raoul Moat, will be on the streets himself.
He is competing in aid of the Blue Lamp Foundation, which he set up to support people in the emergency services injured in the line of duty by a criminal act.
Pc Rathband said his preparation had been a mental struggle as well as a physical test.
He added: "It's a very lonely place when you're training. I've been to some very, very dark places, and I've had some visitors that I'd choose not to have. But they pop along and I try to run them out, and I've managed to do that.
"But it's public knowledge that the trial (of Moat's helpers) went on for a very long time and it ripped my wife and myself apart for the second time, and I'm still trying to rebuild my strength, energy and health."
Two men were convicted at Newcastle Crown Court last month for helping Moat during his shooting spree.
Pc Rathband added that he had no finish time in mind for the marathon and is only aiming to "beat the road sweeper".
