However, at 10 years old the £3K battery bill might render the car scrap meaning that electric cars might be getting scrapped earlier than normal. This isn't very "green" surely and how do we cost this extra expense, cars not lasting as long?

Electric cars should last a lot longer than a petrol or diesel as there will not be so much to go wrong, iirc prius battery cells can be replaced so no need to replace whole pack

and with battery tech advancing like it is they will last longer and are recyclable as most are now.

the mention of smart meters, I have one and find it easier to work out what electrical items are the most expensive to run, so if the car charger is rigged through it which it should be (unless it has its own meter) it will be easy to work out cost of running

I would say that £3k for a battery replacement for a hybrid, never mind a full-electric car, even today, is very much on the low side. What also needs to be factored in is that batteries, even Lithium ones, still lose their ability to take and keep a charge as they age - not as much as NiMH or NiCads, but still reasonable at the 5+ year mark onwards.

It means then that, as well as potentially having to spend several £000s to replace the batteries when the car overall is worth less than £3k, the performance and range of the vehicle is less, possibly quite a bit less than when new.

I agree that the cost of replacing the batteries can make such older cars uneconomic to run at an earlier age than ICE cars, but the battery performance issue makes it even worse, far more than a car which, if maintained to a reasonable standard, will probably drop 10-15% of its engine power, much less than the 30-50% drop-off in battery performance when they get older. I'm not sure that battery tech has changed quite to the degree you believe, especially as regards their 'environmental credentials' and recycling. Doing so is very difficult and energy intensive to recover the useful (and harmful) materials and thus cannot (yet anyway) be considered to be that 'green'.

That said, I don't think we should shy away from the technology - I just don't think countries should be 'dashing' for it so soon as we stupidly did for diesel-powered cars when the science was never there to say either was a better technology to use in most circumstances - both have their benefits and uses, but across the board in 20 years - I seriously doubt it.

That and the charging infrastructure (especially for those of us living in flats, require on-street parking or who aren't well-off) and capital costs are just not viable - I personally think many of EV's advocates are about 20-30 years ahead of what is possible in their pronouncements (I think we're 40-50 years away at least, perhaps more, not 20-25), often because they are heavily invested in it financially and have a vested interest in saying it is viable, just like diesel 15-20 years ago.

However, at 10 years old the £3K battery bill might render the car scrap meaning that electric cars might be getting scrapped earlier than normal. This isn't very "green" surely and how do we cost this extra expense, cars not lasting as long?

Fair point, but consider this too: most diesels will need a DPF replacement at around 80 - 100K miles, and with all petrol cars now being fitted with them, those DPFs may need replacing too. This can also add to the cost per mile of running of conventionally-engined cars.

I suppose the electric car doesn't have many parts that "wear out" except for the battery, so all the cam belt, DPF etc costs get offset making things a bit more even.

However, at 10 years old the £3K battery bill might render the car scrap meaning that electric cars might be getting scrapped earlier than normal. This isn't very "green" surely and how do we cost this extra expense, cars not lasting as long?

Fair point, but consider this too: most diesels will need a DPF replacement at around 80 - 100K miles, and with all petrol cars now being fitted with them, those DPFs may need replacing too. This can also add to the cost per mile of running of conventionally-engined cars.

True, but an electric-only car, even after any government grant, still (on a like-for-like basis) costs £5k - £10k more than a diesel, which in turn costs £2k more than a petrol (for a C-sector car). The depreciation, once the electric-only (or some hybrids) battery replacements is factored in is far higher, and I suspect that the replacement cost of a DPF is far lower than that of an EV's entire set of batteries.

At least with ICE engine vehicles they can be parked overnight anywhere and filling stations are a plenty. I live in a flat and sorry, but there's NO WAY our residents association is going to stump up several £000s per flat, plus insurance (in case they get vandalised or bumped into and broken by vehicles using a space [resident or not]) and ongoing costs to repair roads dug up to lay new electrical cabling for one flat, let alone over 50. Imagine what it would cost for an estate with many large tower blocks and hundreds or cars? I shudder to think.

No - this has to be saved up gradually over 30-40 years minimum, so that any work (once the technology is fully mature, actually environmentally friendly and cost effective [which it currently isn't for the vast majority of us, despite what many say]) can be afforded and programmed in so that it can be done at a lower cost when other major works are being undertaken, e.g. major road resurfacing or other significant utility works.

Like most new technology (like TVs), it should be rolled out slowly, meaning the rich get it first (cost grounds), then it gradually filters down to everyone else as costs reduce and technology/benefits improve. I think the green lobby and government/political parties are jumping the gun by going from (effectively) zero to full deployment in 20 years.

The implications for rushing it without thinking through things properly or doing little useful R&D for years (as we've seen with going diesel, HS2, 'smart' utility meters, internet/privacy laws, etc etc) is VERY BAD, especially economically, as this will be FAR more expensive than all those I mentioned put together. We certainly shouldn't listening to the EU, given their horrible track record in such things.