Former professional rugby player David ‘Jacko’ Jackson is coming to the end of an extraordinary world-record-breaking challenge that will see him run 100 ultramarathons in 100 consecutive days.

The North Wales runner hopes to raise £100,000 for brain injury charities Headway UK and Head for Change through his challenge, ‘Mission IN-possible’.

Starting on 29 May and finishing on 5 September, Jacko will have spent 100 days pushing the limits of human endurance by completing a 50km ultramarathon every day without a break.

The feat has broken the current men’s world record for consecutive ultramarathons, which previously sat at 80 days; Jacko completed his 81st ultra on 17 August.

Mission IN-possible has taken Jacko across the UK, welcoming supporters to run alongside him.

In 2013, Jacko’s professional rugby career with Nottingham R.F.C ended abruptly due to a traumatic brain injury and seizure on the pitch during a pre-season training session.

For months, he experienced fatigue, sensitivity to light and cognitive issues, and is grateful to have recovered the way he has. But he is aware not everyone with brain injury has the same access to recovery, rehabilitation, or long-term support.

Jacko said: “Mission IN-possible has not been easy and has been a huge stress on the body, but is nothing compared to the brain injury that I recovered from, and nothing compared to someone who may never recover fully.

“That’s why this challenge is for Headway UK and Head for Change, and for people whose lives are changed forever by brain injury.

“These charities support individuals and their families, and work to improve life after brain injury.”

It took seven years after his injury for Jacko to run his first-ever marathon.

Now he is close to completing 100 ultramarathons in as many days.

Jacko will finish Mission IN-possible on Saturday, September 5 at Caernarfon Castle.