I recently had to look at several banks' websites to answer another question on AB. It quickly became apparent that most charges are common to all the major banks. I've just checked the website for the Royal Bank of Scotland and, as Dzug suggests, the charge is �10 (unless the cheque was lost or stolen).
OneEyedVic is, of course, correct in stating that you can't stop a cheque which was supported by presentation of a cheque card.
If you've sent a cheque through the post or handed it to a mate and guaranteed it then you can cancel it. The guarantee bit only comes into play if it's done, for example, in a shop and it's the shop that do the guaranteeing.
Beyond that, ask your bank how much. That's much easier, quicker and more accurate than asking here. With some banks it costs nothing, with others, apparently a tenner.