Harry Mount, whose father Ferdinand Mount was head of the Downing Street policy unit in the early 1980s, said Prince Charles deserved the honour after “seven decades of slogging round the globe”.
Mr Mount waded into the row amid fears Prince Charles will not succeed the Queen in the role as head of the Commonwealth.
He said: “Yes, it’s true that Prince Charles doesn’t command the same respect as the Queen – as Amitav Banerji, the Commonwealth secretariat director of political affairs, allegedly said in a 2009 diplomatic cable exposed by Wikileaks.
“But then again, no one else in Britain commands the same respect as the Queen. She is almost universally admired, after never putting a foot wrong in 66 years on the throne.
“But who on earth is better qualified than her eldest son to take over? He knows the Commonwealth back to front. He has stood in for his mother on numerous Commonwealth occasions.
“And the Queen herself wants him to take over.
“In 1958, she declared, in Letters Patent, that Charles and his heirs and successors should become the Head. “
In her indirect way, she signalled as much at the Commonwealth Heads of Government Meeting in 2015 in Malta, where she was accompanied by Prince Charles and the Duchess of Cornwall.
“In her opening speech there, she said she could not ‘wish to have been better supported and represented in the Commonwealth than by The Prince of Wales who continues to give so much to it with great distinction’.
“As so often, the Queen sums up the position fairly and succinctly. Her boy should get the job.”
Last year it was reported Prince Charles would eventually step into the role but the Commonwealth Secretariat insisted yesterday a decision would only be taken on the Queen’s successor after the death of the 91-year-old monarch.
Prince Charles will become King on the death of his mother but the head of the Commonwealth is not a hereditary position.
A “high-level group” of Commonwealth officials are set to meet in London and the agenda for the all-day summit is understood to include a discussion of “wider governance considerations”, which insiders say is code for the succession.
A senior source said: “I imagine the question of the succession, however distasteful it may naturally be, will come up.”
The Queen turns 92 in April. She was proclaimed head of the Commonwealth at her coronation when she became head of state in seven of its eight members. Today it has 53 members, mostly former constituents of the British Empire.