An Afghanistan veteran is preparing to run more than 450km in seven days, with a 13kg barrel strapped to his back.
Andreas Beirne is hoping to raise £20,000 for mental health charity Combat Stress.
The total distance of 456km is the equivalent of 11 marathons - a number that holds significance for Andreas.
"Four hundred and fifty-six is the number of British deaths in Afghanistan. Each kilometre for each death," he says.
"I am going to start at the London Marathon. I am going to run from London all the way home to Salisbury."
Andreas was 19 when he served as a private in the Army for six months in Afghanistan in 2009.
He says many of those he served with have sought help through charity Combat Stress and that he now wants to give something back.
"The barrel is kind of heavy, it is 13 kilos, it stretches out quite far as well, but the barrel does need to be tight to me so I have a chest strap and a waist strap at the bottom as well," he says.
"I am running between four, five times a week at the moment, up to 150km a week, so quite a lot of training, but as the weeks go on I am going to be adding 20, 30km on each week.
"So I have got up to 65km a day, three to four times in that week, and then I feel like I will be ready for the challenge ahead."
When asked if he was feeling confident he said:
"Yeah fairly confident, like I’ve had a couple of bad spells with the training, I have got a small knee injury - but that is going to be gone in the next couple of weeks or so.
"I have got a real positive mind and a real positive outset on it and a great team behind me as well.
"I am really confident in the challenge ahead - no matter what, I am going to do it anyway."
He will run the London marathon on 28 April and then will run an average of 40 miles a day for the following six days.