Apparently his girlfriend shouted "get off me" and "get out of my flat". There were reports of loud shouting, including BJ shouting "get off my fucking laptop", and screams. I believe it was reported that the laptop was damaged.
When we heard something like this happening next door many years ago, we called the police because we feared for our neighbour's and her young daughter's safety. My work colleague said she would never contact the police in this sort of situation because it's nobody's business when couples row and "sometimes women provoke men". This surprised me, especially coming from a woman.
I think, in these particular circumstances, it was reasonable to record what was happening. Powerful people have ways of making this sort of incident disappear. It was interesting that, at first, the police denied having attended a domestic incident at that address.
I do have some misgivings about the recording being handed to the Guardian. We've had a few loud rows over the years - though no screaming or indications of violence occurring. I'm glad our neighbours didn't record them!
On the other hand, as BJ is a candidate for PM perhaps people ought to be aware of yet another example of his lack of judgment and self control.