British Prime Minister Gordon Brown today handed over Britain's participation contract to Shanghai Expo organizers, which marked the country's formal acceptance of the invitation to join the grand event.

The cost of UK's participation in Shanghai Expo will be 10 to 12 million pounds. It will be split 50-50 between the public and private sectors. GKN plc, BP and Astra Zeneca have already signed up as corporate sponsors.

UK has already selected its pavilion concept out of six candidates last September after the country exhibited the designs in Shanghai as well as in London to ask public's opinions.

The chosen design is a fascinating lit cube which designed by Heatherwick Studio. The pavilion looks like a box with thousands of spines that hover without visible support above a public square.

The UK Pavilion has a 6,000-square-meter plot on the east bank of Huangpu River. UK is expecting its national pavilion to attract 50,000 visitors a day during the six-month Expo period.