Actually it also happens with other services - ie government phone numbers.
There is a website that in theory offers you recording your call at premium rate - let's say £2 per minute. They advertise as one of the govt numbers regarding "something". So you search for ie "uk self employment contact number" and their ad shows up on the first place with description being similar to what you would expect.

You call that number, they connect you to the proper number (so you can talk without suspecting anything) but charge you £2 per minute. My wife fell victim to this scheme and there was nothing we could do about - the phone company said it is legit business and our fault - 30£ down the drain :(