In reply to JMGLondon:
Are there regulations on this? I'm not sure. I think it's OFT territory ie:
An advert is misleading if, by its words or image, it deceives or is likely to deceive and so persuades, or is likely to persuade, you to spend your money or to change how you spend your money (for example, by persuading you to change from one credit card to another). Misleading adverts may: contain lies; leave out or hide important facts; make a promise which will not be carried out; or create a false impression - even though everything in it may be true.
What the law says
One of the duties of the Office of Fair Trading (OFT) is to help control all advertising, except that on TV and radio and for certain types of financial investments. They can ask the courts to stop any misleading advert. OFT can only act if they get a complaint about a particular advert. They have no power to get compensation for anyone who may have lost money as a result of a misleading advert