It's been run every year since 1981, and is one of the most popular 'public competitor' events in the world, but from next year, 2020, the London Marathon is to undergo a massive identity transplant - it will be known as the London Snickers.
The news was announced today by the race organisers.
Indeed, all so-called 'marathon' events - that is running races over a distance of 26 miles and 385 yards - will now be called snickers, including that in the Olympic Games.
The race will be known as the Olympic Snickers.
It's not known what set of circumstances brought about such a ridiculous change.
A spokesman for a chocolate bar manufacturer later told us:
"We've won a major sponsorship contract, but, as usual, the London guys have got it wrong. We want it called the Snickers London Marathon, but they seem to have missed the whole point."