Petrolhead Jeremy Clarkson is unlikely to be breaking any land speed records on his latest Leicestershire-built ride.

The Top Gear presenter has been spotted behind the handlebars of a heavily-modified version of a mobility scooter made by Sileby firm Pro Rider Mobility.

The TV presenter is understood to be taking on co-hosts Richard Hammond and James May in an off-road challenge on Sunday's show. His machine is an eight-wheel souped-up version of a Road King – the firm's flagship machine.

Pro Rider owner Simon Betts said he was somewhat perplexed when producers first contacted him with their plan.

He said: "I understand the premise of the challenge is for the three presenters to race each other up Mount Snowdon on mobility scooters.

"It sounds crazy but we're all massive fans of the show here so we agreed to help."

The firm was asked to provide a Pro Rider for Clarkson to race, with Hammond and May on modified scooters found from other manufacturers.

Simon, 44, said: "It's the most powerful scooter we do, with an 1100-watt electric engine and a battery that lasts 30 miles on one charge.

"It's designed for, shall we say, the more sturdier person and can be driven on the road. The programme bought two scooters, we supplied £3,000 worth of spare parts free."

The next few weeks were clouded in mystery and intrigue for technicians at Pro Rider as their counterparts at Top Gear quizzed them for advice and know-how.

Simon said: "They were forever on the phone bombarding us with questions.

"Jeremy was adamant that he wanted the machine to go faster and we had to re-programme the computer because they are only allowed a top speed of 8mph by law."

The firm ended up sending down 18 extra batteries, two spare motors, a new suspension, two sets of super-sized wheels and tyres and two complete chassis rear ends.

The team at Pro Rider got a sneak preview of the final result when footage of Clarkson and co test-driving the scooters in Abergavenny high street appeared on the internet.

Simon said: "Its incredible. They've stuck two whole scooters together, with two motors and eight massive wheels. I think its amazing – and very funny – it looks like the mobility scooter version of a monster truck."

Simon and his team have been invited to join the Top Gear studio audience later today for the show, which goes out on BBC2 at 8pm on Sunday.

Business is booming for Simon, a former school teacher from Oadby who set up Pro Rider seven years ago.

The firm, which also makes electric golf trolleys and bikes, employs 12 people in Sileby and made a turnover last year of £3million, 150 per cent up on the previous 12 months despite the recession.

The firm has sold 2,000 Road Kings at £939 each in the past year.

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