Staff tentatively opened the doors at 9am to an onslaught of women, who made a beeline for the collection by the famous designer.
Rails of stock were cleared within minutes, as the locust-like crowd scooped up armfuls of the much sought-after gear.
Shop staff struggled to replenish lines, but many were forced to abandon all hope as shoppers grabbed clothes from their arms. Some assistants resorted to dumping new stock on tables.
There were heated scenes in the crowded changing rooms as shoppers snatched items from one another. On the shopfloor, the atmosphere was more tempered, as customers set up makeshift changing rooms and swapped cast-offs. The potential of selling the clothes on eBay was a hot topic of discussion.
Sheila Temple, a 61-year-old retiree, travelled from Guildford to pick up a green dress she had seen in a magazine. She said: 'It's an excellent collection. It reaches people who can't afford designer clothes.'
Gemma Aldridge, a 22-year-old PA from London, was hunting for a pair of McCartney's trademark skinny black trousers. She said: 'I've seen the stuff on the internet and it looks great.'
The one-off collection, comprising 40 different pieces and accessories, launched at 400 H&M stores worldwide, backed by a high-profile TV and magazine ad campaign. It received an extra bout of publicity when supermodel Kate Moss was dropped from the marketing campaign for drug abuse.