This has been on and off for a while but seems to be back in favour again. There is a House of Commons select committee looking at it and it could be introduced "within weeks" apparently.
I have just had my p38 MOT'd and the mileage I did from the previous MOT in 2020 was only 350 miles. Admittedly it was SORN'd for 5 months.
I quite fancy getting a second p38, maybe a decent petrol one and just leave it parked out in the road to be used now and then. If it is not used, it costs nothing.
I hope the new scheme is not going to be half and half. A fixed charge and a mileage charge. I have got a shed full of spares I have collected over the years to run a second, even a third.