They are photographers, not terrorists!

Even before the midday start time, photographers - amateur and professional - grasping thousands upon thousands of pounds worth of camera equipment are descending on Trafalgar Square.

Is it a pack, gaggle, a snapshot or a click of snappers?

Who knows, but either way there's a hell of a lot of them and they're all here for the I'm A Photographer Not A Terrorist mass photo gathering; a flash mob with flash guns.

By 12 there's a fair couple of thousand of photographers, all looking for that perfect shot, leading to an interesting scenario where the photographers, instead of documenting someone else's story, have now become the story themselves.

So at 12.15pm, when a school portrait style group shot is set to take place on the steps of the Square, everyone gets slightly confused as to whether they should be taking the picture or starring in it. "Cheeeese," announces the grinning crowd as the sound of hundreds of shutters snapping fills the nippy winter air.

With pint sized placards doing the rounds, there are, handily, plenty of photo opportunities. The person in the fluro jacket and Guy Fawkes mask à la 'V For Vendetta' understandably gets a lot of love from the lenses, as do those sporting hoodies and T-shirts emblazoned with the event's slogan as well as the person in the gorilla suit - there's always one, isn't there?

Then there are the things that no one can quite see what anyone is taking photos of, but people get involved in the spiralling, circling pits of snapping because, well, it seems like fun. And it is.

Less fun is the moment all the photographers are ordered down from the steps at the entrance of the National Gallery, which looks out over Trafalgar Square, and which provide a perfect vantage point for an all encompassing shot of the event.

People are shooed down the stairs, and flimsy barriers are placed at the bottom of the steps, but not before one young man argues his case to a security guard who shakes his head as the on-looking photographers give him a boo worthy of a pantomime baddie.

In amongst all the snapping and shooting, 'Stop and Search Card's, worded by Mark Thomas are being handed out, to be shown in times of need.

"I pledge to waste your time if you decide to waste mine," they say, informing officers that if the stop and search they carry out is intrusive, unlawful or malicious, a complaint will be made to the Police Professional Standards Department and then to the Independent Police Complaints Commission.

With the cards duly placed in camera bags, an announcement is made thanking the crowd for their attendance and informing them of that all important next step, a well deserved trip to the pub.