The RAF has launched an investigation over photos apparently showing at least one serviceman posing beside the body of a dead Taliban insurgent in Afghanistan.
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.