Still need coins in London?

http://hi-tecwashrooms.co.uk/paid-toilet-entry/contactless-entry-systems/

You may occasionally need some coins, but I can only recall one time in the past few years when this has been necessary - in Tenby in South Wales. There are free toilets in department stores, cafes, restaurants, shopping centres, supermarkets and in some places, council run facilities, although many of these have closed due to a lack of cash.

I have never been anywhere where you can pay by card as it’s usually cash.

In 2017 we did four weeks driving all over S. Wales and England. We needed coins for parking and the WC. That is about it.

Here in the USA, I never use coins. I don't use cash except in a couple of places, my barber shop doesn't accept credit or debit cards.

I'm in the UK often and carry some cash and coins. Except for taxis--my choice--I've never had to use cash. I also can't remember being charged to use the loo.

I can't recall ever having the need to pay to use a toilet in the UK more than once, and i have lived here for 74 years

There are public toilets near the river in Witney, Oxfordshire which accept a 20p piece. Not far away is a Waitrose which I am sure would not charge.

The excellent public toilets in Broadway, Glos., are free.

I can't think of any London public toilets, there are plenty of places to "go" nearby though.

I don't remember if the TfL toilets on the Piccadilly Circus station charge or not.

There is a policy in place at TfL to remove all charges on its station toilets although this might not have been fully implemented yet (locks needing to be changed on cubicle doors etc).