For a man who has ridden the entire Tour de France route during the race itself – setting off at 4 a.m. each day to avoid being caught by the pros – riding a small mountain-bike race far removed from cycling’s European heartland should hold no fear. But, although there may only be a dozen or so participants, this isn’t just any mountain-bike race. This is the Tour Divide.

Running from Banff in Canada to the Mexican border, the Tour Divide is, at more than 2,700 miles, the longest mountain-bike race in the world. Not only is it 500 miles farther than the Tour de France, its route along the continental divide goes through the heart of the Rocky Mountains and involves more than 200,000 ft of ascent – the equivalent of climbing Mount Everest seven times.

The other problem is that Howard has never owned a mountain bike, and even when he does finally get hold of one, how will training on the South Downs prepare him for sleeping rough in the Rockies? What’s more, the ruthlessly efficient back-up team that helped Howard in the Tour – his dad – will be absent. In fact, the race rules stipulate that riders must be entirely self-reliant.

Undaunted, Howard swaps the smooth tarmac roads of France for the mud, snow and ice of the Tour Divide. Instead of fending off attacks from Lance Armstrong, he has to deal with grizzly bears, mountain lions and moose. Millions of buzzing roadside fans are replaced by millions of buzzing mosquitoes. Worse still is the unshakeable fear of meeting the original rednecks from the film Deliverance hiding behind the next tree...