You're simplifying matters. If money was clearly sent in error, the bank can protect it from being spent (and subsequently refund it), unless the recipient disputes it:
> When you notify your bank or building society that you have made an electronic payment to the wrong account, your bank will commence action on your behalf within a maximum of two working days.
> Where your bank finds clear evidence of a genuine mistake, they will contact the receiving bank on your behalf with a request to prevent the money being mistakenly spent. As long as the recipient does not dispute your claim, you will subsequently receive a refund of the protected funds within 20 working days from when you notified your bank.
> When you notify your bank or building society that you have made an electronic payment to the wrong account, your bank will commence action on your behalf within a maximum of two working days.
> Where your bank finds clear evidence of a genuine mistake, they will contact the receiving bank on your behalf with a request to prevent the money being mistakenly spent. As long as the recipient does not dispute your claim, you will subsequently receive a refund of the protected funds within 20 working days from when you notified your bank.
http://www.fasterpayments.org.uk/press-release/new-help-cust...