Britain's Queen Elizabeth II praised the response of London and Manchester to horrific terror attacks this year, during her annual Christmas message on Monday.

She also paid a personal tribute to the ‘support and unique sense of humour’ of her husband Prince Philip, who retired from solo public duties in 2017.

‘This Christmas, I think of London and Manchester, whose powerful identities shone through over the past twelve months in the face of appalling attacks,’ the 91-year-old monarch said in the pre-recorded televised message.

London suffered two deadly attacks, while 22 people -- including many children and teenagers -- were killed in a suicide bombing at Manchester Arena where US singer Ariana Grande had been performing.

The Queen described a hospital visit immediately after the Manchester attack as ‘a privilege because the patients I met were an example to us all, showing extraordinary bravery and resilience.’

The world's longest serving monarch also praised her 96-year-old husband, saying: ‘I know his support and unique sense of humour will remain strong as ever as we enjoy spending Christmas with our family, and look forward to welcoming new members into it next year.

‘I don't know that anyone had invented the term 'platinum' for a 70th wedding anniversary when I was born. You weren't expected to be around that long,’ she added.

‘Even Prince Philip has decided it's time to slow down a little, having, as he economically put it, 'done his bit'.’

Flanked by pictures of great-grandchildren George and Charlotte in her Buckingham Palace home, the Queen said that ‘home’ was the theme of this year's message.

‘We think of our homes as places of warmth, familiarity and love... there is a timeless simplicity to the pull of home,’ she said.

Prince Harry's bride-to-be Meghan Markle is the first fiancee to spend Christmas with the British royal family -- a move hailed as a sea change in the monarchy's traditionalist attitude.

The US actress joined the royals at Sandringham, the Queen's private estate in Norfolk, eastern England, where the royals traditionally spend their winter break.

Wearing a brown coat and hat, boots and bag, Markle walked with future husband Harry, his brother Prince William and his wife Kate on their way to St Mary Magdalene Church for a Christmas morning service.

Hundreds of wellwishers had gathered for their arrival.

It is understood that Harry and his fiancee are staying with Prince William and the Duchess of Cambridge Kate at Anmer Hall, their home in the Sandringham grounds, rather than in the main house.