Chris Thrall is aiming to run 26 miles per day (Picture: SWNS).
A Royal Marines veteran is running at least a marathon a day as he jogs the length of the UK from John O'Groats to Land's End for charity.
Forty-seven-year-old Chris Thrall is taking on the 999-mile journey whilst carrying a 14-kilo backpack, as well as food and a tent to sleep in.
Mr Thrall started in the north of Scotland at the beginning of September.
The veteran is running at least 26 miles each day, a marathon, as he aims to complete the challenge within the next two weeks.
Mr Thrall, from Plymouth in Devon, served with the Royal Marines but struggled when he returned to 'civvie street'.
He found himself in Hong Kong, addicted to crystal meth and working for the 'Triads' gang.
The veteran told his story to Forces Network last year.
Mr Thrall said: "After leaving the Marines, it can be a big shock for some people.
“If you add to that a traumatic experience, then it extenuates the confusion of the situation.
“When you start relying on drug and alcohol to release the stress, it could end up compounding.
“It is a change of culture. There are different rules and a different set of ethics outside the military.
“It can be very hard to come to terms with - the lack of depth which passes for OK in civilian life, the lack of people who have got your back, being in the workplace with people treating you like dirt.
"Military people make up an unusually high proportion of people sleeping rough, maybe more resources need to be put into that."
Mr Thrall said he "nearly lost everything" in Hong Kong and that he "completely lost" his mental health.
He hopes his '999 Mile Challenge' will help others, with all funds being donated to the charity 'Bastion Baton'.
Before embarking on the run, Mr Thrall had undergone four operations on his back and says he was “pretty much disabled” for two-and-a-half-years.
He said: “Everyone is telling me to stop with the run and to rest...but I'm not stopping.
“My partner Jenny is brilliant, she was the one who told me to do it and stop moaning and get on with it.
"I’ve been quite hampered so far as I’ve had four spinal operations and I’ve done no training whatsoever."
On the last stretch of the journey, Mr Thrall will be accompanied by his three-year-old son.
So far Mr Thrall has raised half his £5,000 target.
You can donate here.