The Duke of Edinburgh shared an “absolute lifetime” with the Queen and prevented her from being lonely as she carried out her duties as head of state, a royal author has said.

Penny Junor said the impact of Philip’s death on the Queen – his wife of 73 years – will be enormous.

“The Queen will no doubt have been expecting this for some time,” Ms Junor told the PA news agency.

“Prince Philip was an age when it was inevitable sooner or later, but he has been such an important figure in her life. I think the impact will be enormous.

“They had been together a lifetime – an absolute lifetime.

“He was such a support to her, and a friend to her – a real companion.

“Fundamentally, they made each other laugh. He was someone who kept her feet on the ground, and stopped her being quite so lonely in what really is an incredibly lonely world.”

She added that the monarch knew how to deal with her sometimes difficult husband.

“I think he was a very difficult character, but the Queen knew how to handle him,” she said.

“There were stories about the Queen on the Royal Yacht Britannia, for instance, years ago, refusing to come out of her cabin until he was in a better mood.”

Philip was known for his gaffes, but he was also a moderniser and brought about change to the institution of the monarchy, Ms Junor said.

“He was always putting his foot in it, but fundamentally, he added colour to life,” the writer said.

Ms Junor stressed the key part Philip played in national and royal life, from setting up the Duke of Edinburgh Award scheme to taking charge of the Windsor and Sandringham estates and making them commercial.

The royal writer also recalled how the duke had a sweet side to his nature.

“I remember being in the market town of Dorking in Surrey. It was Easter time, and the streets were absolutely jam-packed with people, and the Queen was on one side of the street collecting flowers,” she said.

“There was one tiny little girl who had a single daffodil that the Queen had overlooked and Prince Philip noticed.

“He went up to this little girl and lifted her over the barrier, and said ‘Go and give your flower to the Queen’, and she did and her day was made.

“So I think, along with a sort of roughness – he definitely could be a bully and he could reduce grown men to tears – there was a rather sweet side to him – a compassionate side.”