"The London Marathon means everything to me," said the 43-year-old Londoner, who has won the event eight times in a career that has also seen him earn six Paralympic and six world titles.

"Back in the eighties it was the only place you saw people in wheelchairs competing," he recalled at a pre-event press conference alongside defending champion Marcel Hug of Switzerland.

"And I said to my parents 'that’s what I want to do'.

"I remember when I first did the mini-marathon the idea of being in the main race was so exciting.

"I’ve probably got a couple more in me.

"I have to get to the 25 mark.

"I will definitely finish my career at the London Marathon - whenever that will be.

"That is a decision I have taken.

"If training had been going badly thinking about finishing would be easier - but it’s been going really well.

"I have been doing warm weather training in Portugal with lots of mileage, although I have changed the intensity of my routine because of my age, and that has worked really well."

Asked about his experience of winning the Paris marathon earlier this month, he added: "Winning in Paris was a confidence booster.

"It was a tough race - Paris changed the course so there were a lot of cobbles, and it was not great weather, and I did it on the back of doing a 120-mile week.

"That was just to finish it off - I’m a lot fresher coming into this race."

Hug reflected upon taking more than a minute off the course record as he won his sixth title in Boston in 1 hour 17min 06sec last Monday despite the rainy weather.

"I certainly didn’t expect to do that," said the Tokyo 2020 champion.

"It was not an easy race.

"I thought it might be possible to make a good time, but when the rain started it was more difficult.

"So I was surprised about that fast time."