Steve Shanks, 45, from Bingham, Nottingham, had completed "many" marathons and finished the event in the capital in 2:53:26.

In a statement posted on social media, his wife Jess said his passing was "out of the blue" and that he had been "returning home having spent the day participating" in London.

"As you can imagine I'm absolutely in shock & devastated," she added.

In a tribute to "our friend Steve", Holme Pierrepont Running Club posted a message on its website to express it was "shocked and saddened" over Mr Shanks' passing.

The club added: "He will be hugely missed and we offer our heartfelt condolences to our friend, his wife Jess."

TCS London Marathon confirmed the news of his death on Wednesday and expressed its "sincere condolences".

The organisation said "everyone at London Marathon Events was deeply saddened" to hear about Mr Shanks' sudden death.

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"All involved in the organisation of the London Marathon would like to express sincere condolences to Steve's wife Jess, his family and friends," TCS London Marathon added.

"A fundraising page for the Multiple Sclerosis (MS) Society has been set up in Steve's memory."

The fundraising page raised more than £4,500 in the first 18 hours.

MS was described on the GoFundMe page as a cause "close to (Steve's) heart" because a number of his close friends have the condition.

"Steve was a keen runner never happier than running anything, from his local Parkrun, to the Bob Graham Round," it continued.

"But he was more than just a runner - he was (a) musician, a knitter, and a renowned quizzer possessed of extensive knowledge of terrible pop music.

"He was a loving husband and soulmate of his wife Jess, treasured son and son-in-law, and a much-loved friend.

"He will be greatly missed and always in our hearts and memories."

An MS Society spokesperson said that although Mr Shanks did not run for them, they were "deeply saddened" to hear of his death.