The anti-monarchist group Republic has urged the British government to follow Australia's example and scrap knights and dames from the honours system.
The Queen has agreed to a recommendation to remove the titles of knights and dames from the Order of Australia, Australian Prime Minister Malcolm Turnbull has said.
The Duke of Edinburgh is now one of the last people to be awarded a knighthood by the country.
Mr Turnbull, a republican who replaced Tony Abbott as prime minister in September, said Australia's cabinet had agreed "knights and dames are not appropriate in our modern honours system".
Graham Smith, spokesman for the British campaign group Republic, argued that the UK honours system was also in need of major reform.
"In any country these titles are silly, completely at odds with modern democratic values and wide open to abuse by the political classes," Mr Smith said.
"In the UK the honours system is little more than a way for political leaders to thank their friends, allies and donors.
"It is shameful that David Cameron has brought back political knighthoods, rewarding colleagues for support or handing them out as compensation for being sacked.
"We need full-scale reform of Britain's honours system - no more imperial honours, no more medieval titles."
The announcement on Australia Day in January that the Duke was to receive a knighthood was widely criticised at the time, with some suggesting it sounded like a joke.
He is already a Knight of the Order of the Elephant in Denmark, a Royal Chief of the Order of Logohu in Papua New Guinea, and a Knight Grand Cross of the Order of the Netherlands Lion - among many other honours.
Heir to the throne the Prince of Wales, a future king of Australia, is about to embark on a tour of Australia and New Zealand with the Duchess of Cornwall.
