"Either we solve the problem as a country or we cancel the ban on new ICE from 2040"
That's what, 4 UK General Elections away? Does anyone think May will actually get elected to a second term?
What's your real end goal here?
De-couple car use from the pollution generation of the power station?
Go carbon neutral for climate change?
Build more nuclear reactors?
Going electric means building a shed load of power generation and distribution infrastructure that simply does not exist, along with the standards to support them.
IMHO any replacement has to be as easy to refuel and as energy dense as gasoline. My instinct says this is a liquid fuel driving a fuel cell using the existing supply chain. It's grown from something, so the processing is as as simple as possible IE it has minimal additional energy inputs. My candidate is sugar beet. It grows in the UK, conversion is well understood and it can be grown organically, so no additional inputs. Unfortunately sugar based fuel cell development is behind other kinds despite the fact that sugar solutions are room temperature storable and non inflammable.