Like G says, there are NO free lunches........however, given that you are lucky to get 1/2- 2 1/2 % paid, and they lend it out at~18%, you are, effectively,PAYING ~ 10% of your balance, for their services.....BUT....banking rules allow them to lend several times more than their deposits...IIRC, It's about 3x....this is because, in the early days of banks, someone realised that only a small percentage of total deposits, actually moved, so ther was only a tiny fluctuation....the story becomes a bit convoluted, there's a good documentary about the Rothschild dynasty, on U-tube....suffice to say, your £100 in a current account, allows them to lend ~300 of non-existent money, which they make their 10% on It's a bit mind-boggling, but goes some whay to explaining the recent near-collapse of world finances and all these toxic loans etc.
Banks do nobody favours, they are legalised con merchants.
pay no charges, they need your deposits, despite their protestations that you are costing them money....If that were the case, your account would have been closed yesterday!