Yes - I’ve just walked over there and it’s a charity event for the Hampshire and Isle of Wight air ambulance. It involves people walking and running round the common.
I think the event is far too noisy - both the music and the PA system. It seems to me to be much noisier than the funfair and other things that happen on the common. And it has occurred (without any warning as far as I know) very soon after the funfair.
I spoke to an ambulance man who said it will finish when the last person completes the circuit and could go on until 11pm. I have just spoken to an out of hours person at Southampton City Council. Apparently environmental health no longer run and out of hours service ‘due to COVID’ so no action can be taken tonight. (In the past environmental health were helpful one weekend when an event was extremely noisy). The council official I spoke to said she would pass on my comments on Monday.
There would be no harm if other residents want to phone SCC. The number I rang is 023 80233344. The message says only hold on if your issue is immediate health and safety, but I hung on anyway and someone answered.