Bacs limit is £20 million per item but is 3 day clearing. The £250k limit is FPS (instant clearing) I believe, or your bank.

You're correct, sorry. AIUI there's a higher limit for corps/govs too. Banks often have lower limits than these but I've no doubt they'll lift them if there's need.

For those not familiar, FPS offers 2h (normally instant) transaction speed.

Having bank transfers in 2019 so slow is outrageous. It's the time when trading bots produce millions in a split second. But bank transactions require hours and days. And they dare to call them fast!

Eh, when does it really matter? The only time I care about speed is when buying something, and the more expensive that something is, the less fast it needs to be.

If you have a truck waiting to load at a warehouse somewhere waiting for your £200k payment to clear, then yes, the speed really really matters.

Same goes for aircraft. Good luck chartering an airliner at short notice without making a large deposit.

the orders might only take a few ms from creation to execution, but the settlement still takes time (hours to days)

2h is quick. In EU sometimes it can take days.