Britain's Queen Elizabeth has spoken out for the first time since the death of the Duke of Edinburgh to thank well-wishers across the globe for the tributes paid to her husband, which have "deeply touched" the royal family.

In a message released on her 95th birthday, the queen said she and her family were in a "period of great sadness", but were comforted by words of praise for Philip who died peacefully at Windsor Castle aged 99.

The couple had been married since 1947.

The queen said: "I have, on the occasion of my 95th birthday today, received many messages of good wishes, which I very much appreciate.

"While as a family we are in a period of great sadness, it has been a comfort to us all to see and to hear the tributes paid to my husband, from those within the United Kingdom, the Commonwealth and around the world.

"My family and I would like to thank you all for the support and kindness shown to us in recent days.

"We have been deeply touched, and continue to be reminded that Philip had such an extraordinary impact on countless people throughout his life."

The birthday falls during a two-week period of royal mourning for the Duke of Edinburgh, who was interred on Saturday in the Royal Vault at St George's Chapel in Windsor.

The queen, seen at the funeral for the first time since his death, cut a solitary figure due to coronavirus restrictions, sitting alone in mourning black, with a white-trimmed, black face mask.

Close family, also masked, were forced to sit socially distanced in the historic 15th-century Gothic chapel during the 50-minute service attended by just 30 guests.

With the ongoing restrictions curtailing socialising, her birthday, which is typically marked with a traditional gun salute and the release of a new portrait, will be subdued this year.

Although the grieving monarch returned to public duties a few days after Philip's passing, there are no plans to mark her birthday publicly.

She is expected to be at Windsor, west of London, where she and the late duke had spent much of the past year shielding due to the pandemic.

"This is going to be a private day for her and that's how it should be," said Joe Little, managing editor of Majesty Magazine.

"I think she will be personally devastated by this, but I don't think the death of the Duke of Edinburgh, her husband of 73 years, is going to impact on her working role.

"There's the public queen and there's the private queen, and she's great at being able to compartmentalise."

Prime Minister Boris Johnson tweeted "warm wishes" to the monarch.

"I have always had the highest admiration for Her Majesty and her service to this country.

"I am proud to serve as her Prime Minister," he wrote.

Britain's longest-serving monarch, now in the twilight of her reign, married Philip in November 1947, nearly five years before she succeeded her father, King George VI.

She has previously described him as her "strength and stay" during seven decades of almost constant presence at her side.

Senior royals have conceded his death has left a "huge void" in the Queen's life, and have reportedly been sharing responsibility to comfort her at Windsor.

The Queen and Philip's grandson Prince Harry, 36, flew back from the US for the funeral, but returned home again to be with his pregnant wife Meghan before his grandmother's birthday, according to media reports in the UK.

Saturday was his first public meeting with the family since a reported falling out over his shock move to California, and his stinging criticism of royal life, including accusations of racism in the institution.

He reportedly spent several hours with his father and heir to the throne Prince Charles and elder brother Prince William following the ceremony, prompting speculation that any enduring rift is being healed.

Although the Queen's birthday is on 21 April, her official birthday is normally celebrated on the second Saturday in June, in a tradition dating back to 1748.

It is marked with an annual military parade, known as "Trooping the Colour", but has been cancelled for a second consecutive year due to the pandemic.