Bristol's busiest shopping centre came to a stand still on Saturday, when hundreds of people took part in a "flash mob freeze".

A flash mob is a large group of people who assemble suddenly in a public place, perform an unusual action for a brief time, then quickly disperse.

In this case it was for participants to hold perfectly still for five minutes at 1pm in Cabot Circus, in whatever pose they chose.

The majority of flash mobbers stood in the centre forecourt in front of House of Fraser, but there were people taking part on every floor.

Some posed in mock fights, others crossed their eyes or froze about to sip a drink in the Soho Coffee Co shop, while many simply stopped mid-stride.

One man, who was taking part in a sponsored 24 hour trampoline-a-thon in aid of Children's Hospice, held a walking pose as he bounced.

Many onlookers took photographs, despite Cabot Circus' policy of requiring permission beforehand, but organisers' fears of heavy handed security preventing pictures did not appear to be justified.

Shoppers looked on in bemusement as hundreds of young people took part in the event, which had been organised through the social networking site Facebook.

Messages were sent to members of the group Bristol Freeze - Cabot Circus, advising them to gather in Castle Park an hour beforehand, although many went straight to the centre.

The group has around 2,500 members though it appeared that only a fraction turned up on Saturday.

They were told the trigger to freeze would be someone shouting "Tina, up here", and the crowd dutifully obeyed.

But until people stopped moving, no one would have any idea how many people would be taking part.

Five Bristol University students from Clifton all heard about the flash mob freeze from Facebook.

Alex Dormon, Millie Forrest, Georgia Collins, Sophie Deveaux and Hillary Smith, all 18, posed in a circle together.

Georgia said: "We did it just for fun, it's about community spirit.

"It would also shock the people who come here."

Phil Maclean, 32 of Taunton, was dressed as Captain America with a collecting bucket to raise money for Children's Hospice.

He said: "I was here because of the charity but I knew this was happening .

"It's bizarre but I got into the spirit of it. It's great fun, why not?"

The trampolinist who posed was JJ Shaw, 31 of Hartcliffe.

He said: "I've been jumping for 20 years so it was ok.

"My neck definitely took the strain though."

A whistle blew to signal the five minutes were up, which prompted a huge round of applause from participants and onlookers before everyone continued on with their day. Within 45 minutes of the freeze, participants had been posted their views on the Facebook group.

UWE student Martin Cassidy said: "Just got back - that was great.

"Cannot believe how many people there were.

"Does anyone think that was noticed enough to make it to a local paper?"

Group creator Mathew White hopes to break a record of 3,000 participants at a Paris flash mob with a future Bristol event.

He said: "We took a collection at the pre and post meet up in Castle Park and raised £79.08, which we rounded up to £80, for Cancer Research UK, so there was some real benefit to the day.

"I wanted to support Cancer Research due to the current news stories regarding Jade Goody and the sad death of Wendy Richard."

If you have any pictures of the event, please email the Bristol Post and you can also upload your videos.