Why is it so hard to find a toilet on the London Underground?

Lemme guess before watching... Money?

Edit: Public London toilets in general have been closed because... money. General bad assumptions about London public facilities or accessibility disregard in the past.

It isn't hard. There's a map here https://content.tfl.gov.uk/toilets-map.pdf Why there aren't more of them is a different question. Whether they're open when you're bursting is another :-)

I saw the picture and thought it was something about Deadpool.