For a product with such a young market you would not expect people to come out at midnight, so it was a surprise

Gennaro Castaldo HMV

There were strong indications of what was to come with pre-orders at WH Smith already greater than those for Titanic and online retailer Amazon.co.uk with a record 36,000 pre-orders.

A WH Smith spokeswoman described the chaos in smaller stores were some shelves were already empty.

"Our Dorking store has reported that it has sold out of videos and other stores are saying that stocks are running low," she said.

"There were quite a lot of parents wanting to buy it as a surprise for their children."

HMV spokesman Gennaro Castaldo said customers were buying the film on both DVD and video.

An estimated 250 people packed its flagship West End store in Oxford Street, which opened at midnight to sell the first copy.

Queues

"For a product with such a young market you would not expect people to come out at midnight, so it was a surprise," he said.

"I think that it is highly unlikely that it will sell out because retailers anticipated the demand - it was always bound to be a huge release."

The West End HMV was transformed for the event by special effects, wizards and witches and even an owl.

Toni Preece, 31, from Eltham, south east London, was the first person in Britain to purchase a video and DVD.

She received a presentation plaque after she queued for 15 hours.

Stores were inundated with pre-orders

All of Tesco's 24-hour shops and 58 Asda superstores have come under Potter's spell.

Asda stores displayed a special Hogwart's Express cashdesk between checkouts nine and 10, a reference to platform nine-and-three-quarters at King's Cross station where the film's namesake, Harry, catches the train to Hogwart's School.

A spokeswoman said: "Sales of the video and DVD are exceeding those of Titanic, and they are selling quicker.

"A couple of stores had children queuing at checkouts at midnight and some had special sleep-over parties.

"At our Livingston store there was a drive-in movie showing of the film in the car park before it went on sale, so there has been a real sense of occasion."