It's a bit of a balanced thing. EV uses electricity from the grid, and electricity production in the UK pollutes (and is about to pour millions of tons of concrete over a marshy wilderness next to Britain's prime bird sanctuary in an AONB and SSI - but's that's another thing). Some people like to ease their consciences by getting a "green tariff" or buy from a "green producer", but it's all just marketeer's window-dressing on the bare fact that everyone who uses electricity from the grid does so at an average of around 1kg of CO2 for 5kWh (this was 2020, when the covid effect made our electricity a bit greener). The only way to improve on that is to use the electricity at times when you know the grid is running more green - but I don't how you can do that practically.
So an EV still pollutes as it runs and, with the current generation mix, it pollutes a bit less its ICE equivalent. Until you take in manufacturing emissions, amortized over the lifetime of the vehicle (whatever the lifetime is for an EV) and at this point all bets are off: it's down to a matter of faith of whether you believe EV is less polluting than ICE or not, but I'm not sure anyone has any facts to offer.
Until about four or five years ago, back when UK electricity was a lot less green, the balance was clearly weighted the other way: EV polluted more, mile for mile, than ICE - forget manufacture. Since then, improvements in generation and in EV design have started to swing things in favour of EV. I reckon it won't be that long before EV is clearly the better option. And as has been said, by then the major manufacturers will be putting out ranges of EV bikes as well as cars.