To sum it up:

At present the old law is still the only law that has any relevance - and that old law is a complete mess, which is the one thing everyone agrees about. It is clear that there is an exemption under which where one or two musicians are performing together in a pub, no entertainment licence is required. But outside that exemption it is very unclear indeed what exactly requires a licence and what (if anything does not.) Local authorities interpret the law in various ways, and it very rarely gets to court, because quite understandiobly, licensees back off when threatened.

Under the new law, when it eventually becomes operative, the situation is clearer. No kind of public musical or dance performance will be legal anywhere in England or Wales unless there is a licence covering it (with the sole exception of places of worship and of any Royal Palaces). We have been assured that getting licences will be very easy and cheap, and that certain types of music-making may not be counted as performances - but until the Guidelines have been produced we are very much in the dark about what all this will really mean, and whether the assurances actually meant anything.