I wouldn't be surprised if there are bugger all ICE cars on sale by 2025 never mind 2030
So far this year BEVs are just over 5% of sales in UK. It is easy in our EV vacuum to think everyone is buying them, but the public are still (rightly in some ways) sceptical. Below is a graph from Deloitte showing expected sales and Europe will be around 15% by 2025, but as UK has higher pentration than Europe average, 20% or slightly more is probably realistic.
Many (most?) manufacturers simply aren't geared up to produce a wide range of BEVs in volume by 2025 and even 2030 will be hard for then. Ford have only launched one expensive BEV and Toyota have none (well one Lexus). Developing EVs isn't as easy as they thought as we see from problems VW (software), Ford and Polestar (both recalls) they have had.
The reality is that in 2030 many manufacturers will have a far smaller range of "plug in" models on sale in UK. They simply aren't going to be able to afford to develop EV (or even PHEV) versions of all their cars. I suspect many will stockpile pre-reg cars before the deadline and sell over a few years as "used". Clearly it would be hard for the government to ban used sales.
Source -
Electric vehicles