Hundreds of people are preparing to take part in the biggest custard pie fight ever staged in Britain.

Pie Fight Brighton is the latest in a growing number of underground stunts arranged anonymously on the social networking site Facebook.

It already has 163 confirmed attendees but some observers have predicted the numbers could swell way beyond 300.

The event will take place on May 24, at the height of Brighton Festival, when Brighton and Hove will be packed with tourists.

Possible locations for the 10 minutes of mayhem include the beach near the Palace Pier, Preston Park or one of the greens in the Old Steine.

The event does not have an official organiser and people are simply being asked to turn up at the chosen location at 3pm.

However the pie fight's mysterious on-line promoters are encouraging people to get dressed up and have even advised participants about how to make their custard pies - using shaving foam.

In an email sent to those taking part they said: "This is just a bit of fun, and we don't want to get in anyone's bad books.

"That way we'll be able to do it again. So we must clear up after ourselves - no leaving any litter - please help clear the place up before we leave.

"Importantly, don't pie passers by.

"Anything you do is your own responsibility, and pieing someone who doesn't want it would probably be assault.

"Likewise, if someone who is playing has had enough and wants to stop, stop....

"This is not an organised event, so you're liable for your own behaviour and the outcome of it.

"Please pie responsibly!"

A spokeswoman for Sussex Police said: "It seems like it could be quite good fun as long as those that are involved with it are willing participants.

"It might be fun for those who are taking part but we would ask them to be aware of others and not to let it get out of hand.

"As long as it is done in the nature in which is intended and people respect passers-by we don't have a huge problem with it.

"They seem to be taking it responsibly by asking people to tidy up after themselves."

On Monday baffled commuters were given a round of applause when they arrived in Brighton station by a group of around 200 Facebook members.

Those gathered began clapping and cheering for commuters leaving the 5.32pm train from London Victoria when a green balloon was released and stopped two minutes later when a red one went into the air.

Last year a crowd of 50 people also took part in a silent party at Brighton station during rush hour, by listening to music through headphones and dancing amongst the commuters.

The event was organised by a mystery group to raise awareness of International Women's Day.