London Flash Mob Singin' in the Rain

TWO HUNDRED people with umbrellas singing in the evening sunshine to the accompaniment of their mobile phones in the courtyard fountains of Somerset House, London's former central record office. What the hell was that about? A bemused security guard and passersby had just witnessed London's second Flash Mob.

Mobsters arrived at precisely 6.25pm from pubs around the West End. Invitations distributed by email earlier in the afternoon asked participants to gather a one of seven hostilities according to star sign, at 6.10pm. Water signs were asked to bring an umbrella.

Instructions for the Flash Mob were distributed in each pub by organisers on a credit card sized piece of paper. Participants were asked to text a mate en route to the venue with the message "call me at 6:30" in order, as it turned out, to provide the accompaniment to the Flash Mob's choral efforts.

Staff at Somerset House appeared to participate in the bizarre phenomenon as they tinkered with the controls for the fountains to the delight of the Mob.

But not everything went according to plan. Mobsters had been asked to click their fingers every time they heard or spoke the letter "Y" and compliment strangers as they departed from the mob. Neither activity appeared to take place.

Mobsters left Somerset House at precisely 6.35pm and walked to nearby Waterloo Bridge where they waved at pedestrians on the adjacent Hungerford Pedestrian Bridge.

London's first organised Internet mob in early August caused chaos in a sofa shop - but it almost didn't happen. Mobsters turned up at Sofa UK on Tottenham Court Road, only to find that the manager Derrick Robinson had sloped off early for a pint in the sweltering weather. But the 250 people who turned up at his shop persuaded him to open up and then complimented him on the quality of his furniture.

Originating in the US, Flash Mobs are carefully orchestrated by email and text message, and have little purpose other than to bemuse and amuse. µ