Thousands of people queued to snap up special offers at the opening of Europe's largest urban shopping centre.
Shoppers ran towards the stores as the doors to Westfield Stratford City, located next to the Olympic Park in east London, were opened.
The £1.45bn complex houses more than 300 shops, 70 restaurants, a 14-screen cinema, three hotels, a bowling alley and the UK's largest casino.
It will provide the main access to the Olympic park for the 2012 Games.
Pop star Nicole Scherzinger performed at an official opening ceremony hosted by Pixie Geldof and Nick Grimshaw.
London Mayor Boris Johnson was also present and was only metres away when a metal roof tile fell and smashed on the floor, BBC London reporter Jason Rosam said.
A spokeswoman for the centre said this happened in "an empty part of the mall".
"No-one was touched and the area has already been cleared," she added.
People began queuing outside the centre at least two hours before most shops opened at 10:00 BST.
Olympians including synchronised swimmer Jenna Randall and rower Andy Triggs-Hodge signed autographs when they opened Next's new store.
And Olympic medallist Colin Jackson launched the first Lloyds TSB branch since 2004. Customers were able to have their photo taken with the 2012 Olympic Torch.
So far 95% of the centre has been let. It is claimed that up to 8,500 permanent jobs will be created by the retail sector.
The complex will provide the main access to the Olympic Park and large screens will be displayed along the centre's walkways showing the main sporting events.
Bill Giouroukos, director of operations at Westfield, said: "The retail mix we are putting in place at Stratford will be the next chapter in retail development for London."
Mr Johnson said the project was "setting the pace for the transformation of east London".
He said: "It is one of the most important legacies of the 2012 Olympics.
"It will create 18,000 jobs and, as a result of Westfield's investment, have some of the most modern additions to London's public transport infrastructure."