Two Suffolk runners believe they have smashed a world record in an ultramarathon by continuously completing loops of a four-mile track since Saturday.
John Stocker and Matthew Blackburn started the backyard ultra challenge at midday on Saturday at Knettishall Heath country park, near the border with Norfolk.
The challenge has seen the pair complete a distance of 6.706km - equivalent to 4.167 miles - every hour since they started.
The duo have only been able to sleep, eat and recover in the short time between starting a new lap when the clock ticks over to another hour.
On Tuesday afternoon, the pair believe they broke the world record as they hit the incredible milestone of 316 miles on the 76th hour.
According to the Guinness World Records website, an application for a record can take between 12-16 weeks to be reviewed.
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules here