His first wife Princess Diana, killed in a Paris car crash in 1997 that provoked an outpouring of grief from Britons, had always blamed Camilla for the breakup for her marriage to Charles.

The queen, born in 1926, suffered a backlash from her children's disastrous marriages but now public opinion is broadly pro-monarchy -- at least until she dies.

Veteran Mail on Sunday columnist William Rees-Mogg said: "We have been living through a great reign comparable in length but also in achievement with the reigns of her predecessors, Queen Elizabeth I and Queen Victoria."

Daily Mirror royal correspondent James Whitaker begged to differ, telling Reuters: "I really, really admire her but I don't think she will go down in history as a great sovereign."

He added: "Three of her children got divorced. That is a hell of a fallout in one family by any standards.

"Everything is fine for the monarchy while she is alive. I am not sure it is fine when she is dead. I don't think we want Charles to come to the throne in any real hurry."