Nile Gardiner, former aide to Margaret Thatcher, called Prince Harry and Meghan Markle two of the most anti-British propagandists in the world.
The foreign policy expert was commenting on the Duke and Duchess of Sussex's Netflix documentary which has drawn strong criticism from the monarchists.
Gardiner said, "Not only are Meghan and Harry's vicious attacks on the Royal Family vindictive, nasty and deeply unpleasant, they also project a great deal of hate towards Britain and contempt for the British people."
He added, "Meghan and Harry are two of the most anti-British propagandists in the world today."
The couple is expected to target the British royal family in the upcoming episodes of their documentary.
The royal family was largely spared in the first three episodes of the series which premiered on Thursday.
A large number of people have watched the documentary in the US and the UK.
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