Cracknell cracks – 68 miles short of John o'Groats

After riding non-stop for 46 hours from Land's End, tandem record bid abandoned

James Cracknell, the Olympic rower turned adventurer, has abandoned an attempt to break the record for cycling from Land's End to John o'Groats on a tandem, with only 68 miles to go.

Cracknell and his partner, Jerone Walters, had ridden non-stop for more than 46 hours along the 842-mile route when their support team advised them to stop yesterday morning, about four hours out of Inverness. Cracknell, a double Olympic gold-medallist and veteran of extreme endurance events, described his frustration at having to give up so close to the goal, which he believed was "within our grasp".

A message on the event's website said: "Safety is our priority and we simply couldn't continue." But on his website, Cracknell said later: "The support crew pulled us over, not because we looked unsafe or they were worried about us physically, but because our average speed was lower than at anytime over the previous 48 hours."

He and Walters were hours from beating the 45-year-old record set by Peter Swinden and John Withers, but Cracknell seemed to suggest that his heart simply wasn't in it.

"[The team] detected a 'laissez faire' attitude to the record that hadn't been there over the previous two days," he said. "It was my reaction to being stopped within 60 miles of John o'Groats and a new record that was telling. Previously I may have protested or tried to argue my case but in recovering from my accident last year I've learnt to trust and rely on people around me a lot more."

Last year, Cracknell was nearly killed on his bike, when he was struck on the head by a lorry's wing mirror in Arizona while trying to run, swim and cycle across America in 18 days. He fractured his skull and suffered brain damage which affected his short term memory and left him subject to unpredictable mood swings. He marked the end of an arduous six-month recovery in characteristic style earlier this year, by competing in a 430-mile land race in -50C temperatures on the Yukon peninsula in Canada.

The Land's End to John o'Groats tandem ride, however, has become Cracknell's nemesis. In 2009 he and British Olympic track cyclist Rebecca Romero had to abandon an attempt when Romero picked up an injury. In 1966, Swinden and Withers completed the route in 50 hours, 14 minutes, 25 seconds. Cracknell and Walters abandoned their attempt after 46 hours, 26 minutes, 16 seconds, having set an average speed of 16.7mph.

Cracknell, as the less experienced cyclist, rode the rear, while Walters, a semi-professional time trial cyclist, was the pilot. They were riding to raise money for Headway, the brain injury association, and were accompanied by a 15-strong support team.

Cracknell, who thanked "the amazing people" who backed the attempt, said it would be a long time before he got back on a tandem . "I'll never be able to look at one again without coming out in a cold sweat," he said.