Adding a single socket spur

You could, of course. But it depends on whether the visitor has a commando charging cable. And then you couldn't use the socket so easily for regular power tools (lawnmower etc).

Although I think you can get caravan hookup points with 1x commando and 1x

Theo

The Skoda Enyaq - with a range of over 300 miles - takes 17 hours to charge from flat to full. You're a little pessimustic,

The skoda website says it takes over 39 hours for a 100% charge using a granny cable (which is what we're talking about).

What you could do is take the back box out, drill through the wall near the top of the box, and chisel a bit of rooom above the back hox (only a couple of cm) at the top edge of the hole behind the plaster. Then crimp or solder an extention length of T&E on one of the existing wires so the insulated join goes through the wall above the box, and a second T&E comes back from the outside socket, which is now part of the ring. Depending on the neatness of the join you may need a 20mm+ hole, but it an have sealant at both ends.

Note, a) this is purely for mechanical wiring reasons, there is no electrical problem with the short spur; b) the outside socket should be a waterproof one.

I'm a bit hesitant to recommend Rolec because they're a bit cheap and nasty (by reputation anyway), but they do do things like this:

Then you can later upgrade to the full EV setup by swapping parts:

Theo

Or 6 litres to be a bit more accurate

Fit a coin meter like the ones we used to use on tellys and tell him to bring a lot of 50ps.

Bill

That'll be downhill with the wind behind it though.

Bill

Does that make it sore?

Bill

Plenty of commercial users will never be able switch to electric vehicles, and shouldn't be forced to, but huge numbers of people do less than 20 miles per day and have offroad parking. They can have their own charge point. Lots of the latter will make the switch simply because of the 'saving' on fuel duty and VAT. People who want to travel 300+ miles are going to be disappointed with current technology as Guy Martin discovered last night on C4

What is the alternative given reports about 'red alert'?

Stop paying people to breed ?. The problem is 7.9 billion people, not what sort of lives they live.

"Trolley lorries" on motorways.

Presuming the circuit is properly wired for 32A that's not a problem; any appliance and/or its plug fuse has to deal with its own current limiting. But if you're worried about it you can temporarily fit a 16A MCB or RCBO.

I meant practical solutions not metaphysical propositions.

did you guys see that Electric car program with Guy Martin

He drove one from Land End to JoG charging up at commercial charge points

his fuel cost was twice as much as for the equivalent diesel car

Ouch!