Clocked off! - London Marathon runner's Big Ben outfit can't fit through finish line (VIDEO)

This is the hilarious moment a competitor running the 26.2 miles (42km) of the London Marathon could not quite complete the race - because his Big Ben outfit wouldn't fit though the finish line.

The annual event sees runners from all over the world compete and raise money for charity by making their way around the route of the British capital. This year, marathon and horology enthusiast Lukas Bates attempted to "break the record for the fastest marathon dressed as a landmark" and chose to dress as one of the city's most famous faces.

But Lukas came unstuck exactly as he was due to cross the finish line, failing to fit himself and the costume through the specially built checkpoint, spending a few moments struggling before being helped by a race organizer.

It is not yet know in what time he completed the race or if he broke the record.

Twitter users posted Lukas' fundraising page in the hope his new viral celebrity would lead to an increase in donations toward Alzheimers research UK.

In his fundraising story, Lukas describes the costume as "I have now manufactuered a Big Ben suit which comes in approximately 1.5 metres over my head".

It's a shame Lukas' meticulous measuring didn't extend to the particulars of the finish line.