A Watford woman is set to attempt a Guinness World Record breaking 50 kilometre run - without actually leaving the building.

Ultra runner Gemma Carter, 28, is hoping to become the fastest female to complete 50 kilometres on a treadmill this Friday.

Gemma, a running coach, will have to finish in under four hours to take the title - 12.5 kilometres per hour.

But she said the real test will be in keeping her focus and not getting bored.

Gemma, who formerly ran for Watford Harriers Club, said: "I did some research and realised that other women had attempted the female 50 kilometre challenge but no one had got the official Guinness World Record time, which was a real incentive to give it a go.

"What really interested me wasn’t the physical challenge of completing 50 kilometres in less than four hours, but the mental side of non-stop running on a treadmill at intensity.

"It brings other aspects into consideration that normal ultra races don't - it will test my mental focus and toughness.

"I have been preparing by doing two to three hour-long treadmill runs, just staring at a blank wall, to practice dealing with the boredom and mental side of it."

Sports scientist Professor Greg Whyte said the "brutal" challenge will test her to the limit.

He said: "There is nothing more boring than running on a treadmill.

"But imagine attempting to break the world record for running 50 kilometres on that same treadmill.

"Gemma will have to average over 12.5 kilometres per hour if she is to break the four-hour barrier, a truly enormous task under brutal physical, psychological and environmental conditions.

"Gemma is a seriously tough competitor who has the physical and psychological ability to achieve success but it is not a foregone conclusion - this is a seriously tough record to break."

The run has to be completed under the official Guinness World Record rules, with two time keepers and two witnesses, as well as video footage, and will be undertaken at The Centre for Health and Human Performance, Harley Street, London.

Gemma, who grew up in a family who competed nationally in athletics and taekwondo, has completed more than 20 marathons and now competes in ultramarathons and endurance races between 40 and 100 miles long.

She currently lives in West London and is a member of the Serpentine Running Club in London.

Gemma is dedicated to fulfilling her potential as a full-time competitive runner and one day hopes to represent Great Britain at a major international championship.

To make a donation to Comic Relief in support of Gemma's world record attempt visit www.chhp.com.