Canoeists Etienne Stott and Tim Baillie have been commemorated on a Royal Mail stamp after their unexpected triumph in the canoe slalom.
Victorious Britons who win the top accolade at London 2012 will be commemorated with a series of special stamps and have a post box painted gold in their home towns to celebrate their wins.
More top news
Among those expected to attend the ceremony will be former US President Bill Clinton and ex-Northern Ireland first minister Peter Robinson.
Five people have been killed and 40 injured after a car and knife attack in London on Wednesday.
A wet, wintry night in places with rain and hill snow slow to move away from southern Scotland and northern England.