Campaign group Republic has called the plan to ask the public to pledge their allegiance to Charles during the coronation "offensive, tone deaf and a gesture that holds the people in contempt."

Speaking for Republic, Graham Smith said:

"This oath plan has been widely mocked, and the chances of more than 0.001% of the country taking this seriously are zero. With just 9% of people enthusiastic about the coronation, this plan shows just how out of touch the royals are."

"In a democracy it is the head of state who should be swearing allegiance to the people, not the other way around. This kind of nonsense should have died with Elizabeth I, not outlived Elizabeth II."

"In swearing allegiance to Charles and his 'heirs and successors', people are being asked to swear allegiance to Prince Andrew too. This is clearly beyond the pale."

"This bizarre idea is likely to prove a huge miscalculation, one born of fear that the monarchy is rapidly losing support. They are doubling down on the most archaic aspects of the coronation while trying to include everyone else in the most crass manner. This will not sit well with most people."