Hundreds of Tamil protesters have gathered outside Marlborough House on Pall Mall in central London.
They oppose the presence of Sri Lankan president Mahinda Rajapaksa at a luncheon for Commonwealth leaders, which will be attended by the Queen.
Channel 4 News foreign affairs correspondent Jonathan Miller tweeted these photographs:
The Guardian reports that Mr Rajapasksa cancelled a planned speech at the Commonwealth Economic Forum this morning amid fears of large demonstrations.
Here's what some of the pilots saw from the cockpit during the spectacular Diamond Jubilee flypast.
41 children from all corners of the UK formed a Diamond Choir to perform for the Queen today
In a rare address the Queen thanked the millions who joined the festivities which she hoped would "brighten our lives for many years".