The Banking and Financial Services Ombudsman‘s Bulletin 52 revisits some interesting banker-customer issues that are worth reading including :

• the measure of damages in the case of misleading conduct: there may have been a loss of the opportunity to gain the benefit elsewhere but if the expected benefit was not available in the market, or the disputant would not have been in a position to take up the opportunity elsewhere, there will be no loss (Gates v CML).
• can a bank customer keep money deposited to their account as a result of an obvious error?
  “It is our experience that some bank customers believe that they are entitled to keep money deposited to their account as a result of an obvious error.Although the Monopoly card ‘Bank error in your favour’ may suggest that you get to keep the windfall, in fact the legal position is otherwise.The law in relation to mistaken payments, as between the person who makes the payment and the person who receives it, is clear. The person who receives it is obliged to return the payment unless, in good faith, they have changed their position to their detriment.”