She was right. At 8 a.m., roughly an hour before the doors were supposed to open, about two dozen men swarmed to the front of the line, overwhelming security and dismaying the waiting crowd.

“They are professional gangs, you know, and this is a strategy they have preplanned,” said Ryan Fong, a dejected-looking student at City University London from China who said he had been pushed out of the line by the mayhem. “I’ve seen it before, but never as bad as this.”

“They get in first, buy up all the product, then flog it for five times the price on eBay,” he said. “They are scary men, and I don’t want to get in their way.”

Nerves started to fray, and insults were traded as staff members created two lines, one for men and the other for women. Tears streaked some of the ashen and unwashed faces, to the bemusement and occasional disgust of commuters and bewildered passers-by. The hooded men brandishing duffel bags refused to leave, pushing and shoving until the police eventually arrived, blue lights flashing like the metallic chintz in the store windows.

As 9 a.m. came and went, the store doors stayed firmly closed. People used their smartphones to try to log on to the H&M website to try their luck there, only for it to crash.

“It’s just outrageous; this has been so badly managed it is absolutely disgusting,” shouted one woman sitting on an empty suitcase, adding that she had taken the day off work to shop. An H&M staff member tried to appease her with a perfume sample, emphasizing that, safety concerns aside, they were unable to open the doors given the mass of people outside.