One of the things television engineer Jem Stansfield and I have spent many a happy hour sketching is a reaction-thrust flight system using water as the propellent. We had all sorts of plans, but could never quite convince ourselves it was worth doing on, say, Scrapheap Challenge.

I’m rather delighted, then, to see the JetLev Flyer. A 100+ horsepower pump, housed in a little boat, shove water up a hose and into a backpack at stupid pressures. Which you then use to blast yourself upwards.

It’s ridiculous, but apparently it works – film here. Brilliant.

Oh, and the Telegraph are all over the story again. They’re hot today.