..."that if you do not stop an activity of which you are aware, and which is occurring on your premises, then you are making the premises available for that purpose.

That is what common sense and legal precedent would appear to indicate - however the guidance specifically says "In the case of genuinely spontaneous music (including singing) and dancing, the place where the entertainment takes place will not have been made available to those taking part for this purpose".

That surely must indicate that the guidance means something else. It apparently envisages a situation where the proprietor is fully aware of what is happening and makes no effort to prevent it, but is not "making the premises available for that purpose".

All very peculiar. I can't see how anyone can be confidently predict what a court would make of that.

But that doesn't necessarily matter too much - what matters more is how the licence holder are going to interpret their responsibilities, and as Richard B points out, a lot of the time this is going to mean breweries or companies, rather than publicans. And they are likely to play safe, so far as our type of music is involved, and rule out informal sessions.