Here is an example where Lloyds TSB offered to strike off a 100k debt after it became clear they had likely broken the banking code (the banking code is voluntary, but it does not go much further than legal requirements), and it is by no means the only time UK banks have written off loans because they were wrongly given out to people who could not afford them:

http://news.bbc.co.uk/1/hi/business/4528567.stm