Six giant cranes are unloading 3,000 containers of Christmas goods from a ship said to be the world's largest container vessel.
Emma Maersk - a quarter of a mile long (397m), 200ft (61.5m) high and as wide as a motorway - docked at Felixstowe, Suffolk, on Saturday evening.
It is delivering 45,000 tonnes of goods from China.
Port officials said it would take 36 hours to unload the cargo of computers, books, toys and Christmas decorations.
The Emma Maersk is on the latest leg of its two-month maiden voyage.
After leaving Gothenburg, Sweden, it called at Yantian, in China, Hong Kong and Tanjung Pelepas, in Malaysia, before reaching the UK.
Experts say the vessel's voyage indicates how the focus of global manufacturing has shifted from Europe and the United States to China in recent decades.
The UK exported about £2.8bn of goods to China in 2005 but imported nearly £16bn - a 30-fold increase on 1980.
The Port of Felixstowe said it had seen a 16% increase in Chinese imports in the past year.
But the Emma Maersk's voyage has been criticised by Green Party MEP for South East England, Dr Caroline Lucas, who said giant ships damaged the environment and international trade needed to be managed.
The ship's Danish owner, Maersk, said the vessel was "one of the most environmentally friendly" container vessels built.