Boris Bikes. Despite their weight and impracticality for long rides, they've been ridden up Mt Ventoux, round the route of the first stage of the 2014 Tour de France, and now all the way from London to Paris.

It must have seemed like a good idea at the time. On his blog CycleLove, designer James Greig tells how he agreed to join a refreshingly daft trip – over 300km from the UK capital to the French on London's iconic hire bikes.

Greig writes: "Completely out of the blue, I received a phone call from my friend Graham [McLoughlin] at Borough: “I’m going to ride a Boris Bike from London to Paris. Do you want to come with me?”

"Without thinking I said yes.

"It sounded like a fun trip. And I’d been wanting to do a London to Paris ride for a while (having read about the kind of nutters who do it in 24 hours on single speed bikes without stopping)."

They enlisted friend James Holt as a third rider and accompanied by filmmaker Chris Lawson, and cameraman Colin Greenall, off they went.

Well, almost. First they had to plan a route. Their sanity and lack of training was questioned, but, says Greig, "when we plotted our Airbnb accommodation into Google Maps and crunched the numbers, it seemed perfectly doable — if — we stretched the journey over a few more days than you might usually take."

It's France in the summer after all — what's the rush?

They came up with a route that went London – Brighton – Newhaven – Dieppe – Rouen – Bennecourt – Paris. Here's the tale: