Royal biographer Ingrid Seward has revealed that Prince Philip was "quite unpopular" when he began making "sweeping changes" to the royal household many years ago.
Seward told GB News that the Duke of Edinburgh brushed aside his navel ambitions to "support" his wife, Queen Elizabeth.
She explained: "When the Queen's father became really ill he was he was on service in Malta. He realised then that his naval days were going to be over and that he had to do what he was destined to do, which was support his wife, the Queen, as monarch.
Host Eamonn Holmes asked her: "Ingrid, we talked about his military career there. So he was used to giving and taking orders there and did he take orders in the royal household or did he make the orders?"
Prince Philip was in the navy
Adrian Dennis/Pool via REUTERS/File Photo
Seward explained:: "Well, Philip started to make the orders because he saw that the household was run in a very inefficient way.
"He was an extremely efficient man, he wanted things to run smoothly. He became a little bit unpopular because he started making quite sweeping changes within the royal household to make it more efficient and that wasn't always popular with the established members of the staff that were there."
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She added: "Philip always said my duty is to support my wife as monarch. And that's the position he never wavered from.
"Whatever else he did, he was always supporting his wife, the Queen and I.
"I think that really big sense of duty was what held them both together over the years.
"Apart from the other obvious things like his sense of humour, his loyalty and his ability just to get on with life and get and make things happen. He made things happen.
Ingrid Seward said that Philip always supported the Queen
GB News
"I suppose he was a bit of a house husband, although he would loathe that expression.
The Queen's father died suddenly in 1952 and she was propelled into a position that she hadn't expected for at least another ten years.
"So Philip had to take over the running of the household, the running of the family. He made the decisions. She 100 per cent agreed with him."
The royal biographer also spoke about the relationship between Philip and the now-King Charles, saying that he would have been "very proud of him."
She explained: "He would totally agree with the slimmed-down monarchy. He would be very proud of his son. He was not always proud of his son, He was a very tough father. They didn't get along in the early years.
"Obviously, they did in later life, I do think that he would be very proud of the way that Charles has immediately implemented what he said he was going to do.
"He said that he was going to have a slimmed-down monarchy and that is what he has organised, that is what he has now got.
"It is a little bit too slimmed down at the moment perhaps, he is coping though. He just doesn't want the burden of too many royals upon the British taxpayer."