The mystery of exactly what Jeremy Clarkson and James May were doing tooling around the West End on bikes recently looks set to be revealed on Sunday when Chris Boardman will be on a panel that assesses the “public information film” the pair were filming.

The Top Gear presenters were spotted on bikes earlier this month, Jeremy Clarkson on an upright hybrid bike that appeared to be rather too small for him, and James May aboard a Brompton. The pair appeared to be filming their faces with GoPro cameras attached to the handlebars.

According to the Radio Times, they were making a ‘public information film’ to promote safer cycling. The feature will be shown in the fifth episode of the current series, which goes to air at 8pm this Sunday on BBC Two (10pm in Wales).

The film will be presented to a panel of experts including British Cycling policy advisor Chris Boardman and members of Westminster Council, one of the London boroughs most notoriously negative about cycling provision.

Chris Boardman couldn’t tell us much about the segment as he hasn’t seen the final edit.

“Anything to do with Top Gear is playing with fire, which is why people watch it,” he said. “On the flip side, it’s also a chance to reach a wider (motoring) audience and portray ourselves as ‘one of you’ rather than cycling fanatics. Just normal people with a sense of humour, who’d like to see more cycling.

“I’m not in control of the edit but knowing a bit about making telly, I could see how they could cut it to look several different ways!

“We’ll see on Sunday if the gamble has paid off.”

The theme of the segment explains why Mr Clarkson and Mr May had gone to some lengths to equip themselves with safety gear, including matching helmets, hi-viz jackets and gloves, and sunglasses despite the gloomy day.

It seemed Mr Clarkson’s jacket was so new he hadn’t removed the tags, leading to speculation he was planning to return them after filming.