They can make it illegal if they like but for a punter to be prosecuted it would have to be "found committing", in the act. It might be easier to enforce in a brothel, massage parlour or similar but extremely difficult in a private house as a warrant would be required. It would hardly be a suitable use for the big red key entry method, more a polite knock. By the time they got in, you should have stopped playing hide the sausage and playing Scrabble or discussing your future finances, whatever?