Yeah I forgot about a credit card payment that was due a number of years ago, before I had online banking. I went in 2 days before it was due and paid it cash. I still got a late penalty added brcause cash takes three days to clear.

A bill under £2 and got hit with a fee of £20

In the UK, cash paid at the institution in question clears the same day. If bundled with a cheque (rather than as two separate transactions) it will clear at the same time as the cheque.

I had something similar happen to me many years ago. I took ATM cash from another account, plus what I had in my house and wallet, to make up the amount that an auto-paid credit card bill due on that same day would have sent me overdrawn.

I avoided the overdraft penalties.

The most absurd thing was that the bank, RBOS, callee me few days after about the late fee asking me if i was having money problems... It was a bill under £2 that had just slipped my mind. If they had checked any of my other accounts they would have seen that i had about £50k with them.. . But no a £2 bill has them calling me almost sounding like they were shaming me over an inconsequential amount of money!