London (CNN) Kenyan Eliud Kipchoge will once again attempt to become the first athlete to break the two-hour marathon barrier in an event being staged in London later this year.

Dubbed the INEOS 1:59 Challenge , this race against the clock -- to be staged in late September or early October -- is being backed by Britain's richest man Jim Ratcliffe, the billionaire owner of chemical firm INEOS, which recently purchased British Cycling's Team Sky.

"It's human nature to push boundaries," said the INEOS 1:59 Challenge website. "The drive to learn and achieve more is in our DNA. In Autumn this year Eliud Kipchoge, with support from INEOS, plans to redefine the limits of human achievement by breaking the last great barrier of modern athletics -- the two-hour marathon."

Last week Ratcliffe and INEOS were accused by environmental protesters of "sportswashing" -- using sport to enhance reputation -- an accusation the Briton completely rejects.

Speaking to reporters ahead of cycling's Tour de Yorkshire, Ratcliffe took aim at those who criticized his company's fracking project, claiming the majority of environmental groups he has met are "ignorant" of the process, adding it remains a cheap source of energy.

Eliud Kipchoge is expected to take part in the event in September or October 2019.

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