The Queen has been caught on camera criticising the behaviour of Chinese officials during a state visit to the UK in 2015. During an off-the-cuff conversation with a police commander, Her Majesty said the Chinese delegation had been "very rude" to the British ambassador to China.

Chinese President Xi Jinping made his first state visit to Britain last October, with the Queen hailing the event at the time as the culmination of an "unprecedented year of cooperation and friendship" between London and Beijing.

However, the monarch's unguarded remarks during a garden party at Buckingham Palace on 10 May suggest that the highly-publicised state visit was not as rosy as it appeared on the surface.

'Testing time'

The gaffe occurred when Metropolitan police commander Lucy D'Orsi was introduced to the Queen as the officer responsible for security during the Chinese state visit. Her Majesty, who was being filmed by her official cameraman, was heard saying: "Oh, bad luck!"

Commander D'Orsi then says it was "quite a testing time" for her and that the Chinese delegation was "very rude and very undiplomatic". She claimed that at one point the guests walked out on both her and the British ambassador to China, Barbara Woodward, telling them that "the trip was off".

The Queen replied: "They were very rude to the ambassador."

Xi Jinping, Royal Gallery
Xi was the first Chinese leader to visit Britain in a decadeReuters

The blunder is likely to be a major source of embarrassment for the monarch at a time when the UK is pushing for deeper strategic and trade relations with China.

A Buckingham Palace spokesman told the Guardian newspaper: "The Chinese state visit was extremely successful and all parties worked closely to ensure it proceeded smoothly."

The Queen's off-the-cuff remarks came on the same day Prime Minister David Cameron was caught on camera calling Nigeria and Afghanistan "two of the most corrupt countries in the world" ahead of an anti-corruption summit in London on 12 May.