Deley is best known as a presenter for the Channel 5 programme The Gadget Show but has struggled hugely to adapt to the live presenting role, and has made a series of significant errors in South Korea at the biggest athletics event in the world outside the Olympic Games.

He has also been accused of a lack of knowledge about the sport and before the competition reached the halfway stage, he has been replaced by That Paralympic Show presenter Rick Edwards.

Edwards was initially commissioned with the job of presenting Channel 4's evening highlights slot before being hastily reassigned to fill the void left by Deley.

The broadcaster - who are showing the prestigious event for the first time ever - have claimed that Deley will continue to feature in the coverage of the World Championships but that his role has simply been "scaled back".

"Channel 4 is committed to developing new presenting talent and this extends to our coverage of sporting events," said a spokeswomen for the broadcaster.

"Ortis Deley's role in Korea covering the world athletics has been scaled back but he will continue to be on air for the duration of the competition.

"In total we have a team of 10 commentators covering this event, from Michael Johnson and well-loved British athletes Dean Macey, Katherine Merry and Iwan Thomas to new presenters."

Since the competition began on August 27, viewers have seen Deley's repeatedly refer to his printed script while he has also had to correct himself frequently when he misread his lines and failed to pronounce the correct name of fellow presenters.

His most embarrassing moment came during a studio discussion with London 2012 chair Sebastian Coe about Usain Bolt's disqualification when fellow presenter and former athletics star Johnson was left to announce an advertisement break in lieu of an intervention from Deley.

Deley also told viewers they would see "history in the making as Oscar Pistorius from South Africa makes history."

Channel 4 are using the event - which ends next Sunday (September 4) - as preparation for their coverage of the London 2012 Paralympics, where they will be host broadcasters for the first time ever, and will be hoping that the Deley episode will be avoided.

Contact the writer of this story at [email protected]