Olympic rowing hero and adventurer James Cracknell and cyclist Jerone Walters were making final preparations today for an assault on one of the oldest cycling records in the world.
The pair are expected to start their attempt on the 45-year-old Land's End to John O'Groats men's tandem record in the early hours of Saturday.
The double gold medallist and his cycling partner are setting out to better the record held by PM Swinden and WJ Withers whose time of 50 hours, 14 mins, 25 seconds stands from 1966.
Walters is a time trial specialist who rides with La Fuga Sigma Sport.
The attempt will take the pair up through Cornwall, skirting the edge of Dartmoor in Devon and to the Clifton Suspension Bridge in Bristol, heading north aiming to reach Lancaster 18 hours into the ride.
They then travel towards Penrith in the Lakes and over the border into Scotland via Gretna Green before the last few hundred miles to John O'Groats.
They will raise money for the Headway Brain Injury Association, which gave Cracknell and his family support and guidance following his well-publicised accident in America last year, when he was struck on the back of the head by the wing mirror of a fuel tanker as he was cycling in Arizona during an endurance event.
Cracknell said: "Without Headway's support I would not be making this record attempt. They reach so many families and teach them how to understand and deal with the obvious, and more subtle, effects of brain injury. With their help, my family and I have been able to rebuild our lives together".
Donations to Headway can be made via the link:
The ride will only begin under perfect weather conditions, but expectations are for a 3am departure on Saturday on the first leg of nearly 900 miles of riding.