Wandsworth Council said organisers were inviting people through Facebook to participate in the event in late July.This heinous 'event', then. Care to guess what it might be?
Police officers with dogs will patrol the park entrances and stop suspects, who could face up to a £200 fine.
A naked cycle ride? Oh, no. That's permitted, nay, even encouraged.
This is a water fight. Similar to the one recently in the centre of London that caused so much fuss.
The warning comes after a similarly organised water fight in Hyde Park resulted in disorder and arrests.As blueknight pointed out in the comments to that post, this was yet another example of the few spoiling the event for the many.
Three people were arrested after some 1,500 people got involved in the water fight on 4 June, which continued for eight hours and resulted in the closure of Oxford Street to traffic.
But that cuts no ice with the Powers That Be. They won't have their park sullied by people out to have fun...
Councillor Sarah McDermott, the environment spokesman, said: "We do not intend to sit idly by and allow the park to be used for a mass water fight.Here's a thought, Sarah. Why not cordon off a section of the park for those who want to go ahead with this (or those who don't want to be involved), and crack down hard on anyone who deviates from that?
"Many people may be thinking of attending because they believe it will be a harmless and amusing day in the park.
"Unfortunately experience elsewhere has shown that whenever these events are organised they normally descend quite rapidly into violence, mayhem and misery for the innocent people caught up in it."