Let’s boost that back up with the lines to Heathrow, all underground from Hounslow West and built from 1975-1986.

I’m not opposed to investment, but I think you vastly overstate your case. In the central zone most lines were built in two main phases: subsurface first and then tube. The thirties extensions were largely suburban and included the Central line extremities, much of it was already built. The two new inner circle lines represented a massive investment compared to that.

BR is a daft comparison – the lines closed were largely rural ones transporting air twice a day from Greater Piddling to Little Piddling.

The point about London is that since about 1850 it’s been so big and dense that public transport is the only viable way of getting around it (as I said somewhere else, you could close down all railway lines outside former Network Southeast and the PTE metro areas, and the net result would be annoyance and pollution rather than carnage).

(and closures on the Underground consisted of a few Little Piddling-style branch lines to nowhere at the Met and Central lines’ extremities, and the joke, only-built-because-Parliament-was-bloody-minded Aldwych branch).

I’m saying investment in new lines was low because it was less than a third of the investment that, in the mid-1930s, was considered absolutely essential to keep London moving. I’m also saying that the investment not in new lines was sod-all, because it was (they replaced some trains that were 50 years old, and mended some signal cables).

Much of that 253 mile network is in suburban areas where surface line costs were substantially cheaper or else the underground took over surface lines such as the route to Ongar. In contrast both new lines were concentrated entirely in the very high cost central zone underground. The comparison to total mileage is therefore misleading – if we focus instead on underground mile or on the area within the Circle line the ratio greatly exceeds 14%.

Even 14% represents a substantial investment under the conditions of the time. So your statement that “apart from that there was no investment…” is is technically true but misleading. Apart from the elephant, the room was empty.

stockwell, amersham, baker street, no idea, and baker street (I’ve also lost the password, cleverly). however, I definitely worked DIY Headgear out once, so hopefully it’ll be gettable again…