An accountant who plans to tackle seven marathons in a week next year for charity went to the rescue of a fellow competitor after finding him concussed up a mountain.

Jon O'Shea, 45, a partner at Haslers Chartered Accountants in Loughton, climbed the Kazbegi Marathon in Russia on Saturday as part of an intense training regime as he prepares for the extreme charity challenge.

The Essex accountant will attempt seven marathons in seven days on seven continents in January in a bid to raise £50,000 for charity after losing colleagues, chairman Martin Anderson, 57, and Charlotte James, 22, to cancer.

He will donate the funds between charities St Clare Hospice and Teenage Cancer Trust, as well as local charities and causes that the Haslers Foundation have supported over the years.

During the training marathon at the weekend, Mr O'Shea found fellow competitor James had suffered a heavy fall and knocked himself out at 7,000ft above sea level.

Mr O'Shea said: "It was just after mile 19 and he was plastered in blood.  He clearly had only just regained consciousness and was running back in the wrong direction.

"I turned him around and started to walk with James towards the next drinks station about a mile ahead and had several repetitive conversations. He was clearly concussed.  

"After five minutes or so another runner caught us up and I explained what had happened. 

"He set off to the drinks station to alert them in advance. Incredibly, despite the fact we were in a fairly remote spot, the ambulance arrived in about 10 minutes and they took James off to hospital."

Kazbegi is situated in the Caucasus Mountains.

He added: "After we managed to get him to safety we still had six miles to go and I was now picking my steps more carefully, mostly because the meadow I was crossing was full of cowpats. 

“I struggled across the line in 5 hours 20 minutes, which is not too bad under the circumstances.

"I was pleased to see James later that evening, patched up with three stitches above his right eye but well again.”

Mr O'Shea is now back in Loughton training for a 50km 'Ultramarathon' in London on October 12.

He will began his seven marathon challenge on January 17.

You can follow Mr O'Shea's progress or donate to his challenge, here.