Every now and then I read about a number that seems significant and think that I should write about it, a “Number of the week” piece to sit alongside the 200+ “Word of the week” posts that you can find elsewhere on this Blog. I see that I have never done so. This is my first “Number of the week” piece.

The number in question this week is 15.5. That’s the legal maximum assisted speed, in miles per hour, for an e-bike here in the UK. I learnt about it in this piece on the Guardian website. E-bikes can go faster than that, “if you pedal hard or go downhill”, but the motor should not be offering any help above 15.5mph (or 25kph if you prefer). Other criteria that make e-bikes legal rather than otherwise are also listed: “pedals that can be used to drive the bike” and “an electric motor with a maximum power output of 250W”.

Some e-bikes being used on UK roads are essentially motorbikes: the pedals are not even connected to chains to turn the wheels, and the motors have an output way in excess of 250W. And not just on the roads. If you spend any time outdoors here in West London you will see people riding these things on pavements. Every day.

There’s a strong risk that I’m going to turn into my dad at some point. He put the fear of God into many a young cyclist, mostly teenage boys cycling on the path rather than the road. He would quote maximum wheel size allowed for bicycles on pavements as if he were a traffic cop and order the rider onto the road. But I suspect he might have gone further. I have no evidence that he ever kicked some young offender off his bike but it wouldn’t surprise me. I’m danger of doing it myself.

Recently, at the end of the school day, with the pavements full of kids of primary school age, I challenged a teenager meandering behind us on a hired e-bike. I’d be very surprised if he was paying to use it. I won’t tell you the brand of bike but it shares its name with one of the two main flavourings in 7-Up. And it’s not Lemon. He rang the bell to get us to move out of the way. I turned and told him to get on the road. “I wanna cycle on the pavement,” he said. Moody little fucker. See? I am turning into my dad.

I was with my son and told him, not for the first time, that at some point I’m going to crack and kick one of these bastards off their bike for cycling on the pavement. The kid in question cycled past, doing nowhere near 15.5mph, mobile phone in his right hand, left hand on the handlebar. I contemplated what the damage might be, for him, his phone and the bike, if I stuck out my right leg. No doubt if I ever do resort to such a thing, the consequences will be worse for me than for the cyclist. Maybe that thought will be enough to make me control my behaviour, but I can’t be the only Londoner who feels this way.