Paula Radcliffe has admitted she could not risk sacrificing the chance to run for pleasure alongside her children by continuing to race competitively.

The 41-year-old bade an emotional farewell at Sunday's Virgin Money London Marathon as she ran with the masses, with the charity fundraisers and the club runners for so many of whom she was the inspiration to start running, to bring the curtain down on her glorious career.

"I'm always going to be a runner, I'm always going to be going out running, but now that pressure of everything being on my body, holding together to get to the race in as good a shape as possible (is gone)," said Radcliffe, who admitted to shedding tears behind her sunglasses along the route and who let them flow as she embraced her husband Gary Lough, eight-year-old daughter Isla and four-year-old son Raphael.

"Even getting ready for this it broke down, so that kind of answered my questions that it's time to step back."

The world-record holder, whose body has been battered by a succession of injuries over a career spanning more than 20 years, had to overcome one final Achilles problem to make the start-line on Sunday. The stresses and strains of churning out mile after mile in training made injuries a career hazard, but Radcliffe really suffered.

From the Portuguese joyriders, whose car sped past her on a training run, flinging up a stone which struck her on the knee, as she prepared for the 2004 Olympics, to the poisonous snake bite to her left leg that was already recovering from a stress fracture ahead of the 2008 Games, to the injury to her left foot which ruled her out of London 2012, Radcliffe endured more than her fair share of misfortune.

Further investigation of that final problem saw Radcliffe require a bone graft on an 18-year-old stress fracture and left her unable to run for eight to nine months.

"I want to stop when I've still got time, I can still go out and enjoy running," added Radcliffe, who crossed the line in two hours 36 minutes and 55 seconds.

She was, unsurprisingly, the first of the non-elite women home. "Taking part in a race like this is special, so I can't say I'm never going to jump into one again - and certainly 10k (races) and half-marathons," she said.

"But it's not sacrificing the fact that maybe in 20 years I might want to run one with my kids. And it's not sacrificing the health of my body to be able to just go out and run for pleasure."