Prime Minister Theresa May has congratulated the Queen and Duke of Edinburgh on their “special” platinum wedding anniversary.
She praised the royal couple, who married 70 years ago in the grand surroundings of Westminster Abbey, for dedicating themselves to their royal duty through the decades.
Elizabeth II, who was a 21-year-old princess when she married her consort Philip on November 20 1947, is the first British monarch to reach the milestone.
Mrs May said on Twitter: “Congratulations to The Queen and The Duke of Edinburgh as they celebrate their Platinum wedding anniversary.
“They have devoted their lives to the service of the UK and the Commonwealth – my best wishes to them both on this special occasion.”
Other messages came from the Women’s Institute, of which the Queen has been a member longer than she has been married to the Duke, joining the Sandringham branch as a princess in 1943.
“Congratulations to HM the Queen and HRH The Duke of Edinburgh on their 70th wedding anniversary today,” the WI said.
Kensington Palace also tweeted its congratulations, wishing them “a very happy 70th wedding anniversary”.
A series of new portraits of the royal couple were released to mark their anniversary.
The photographs, taken by British photographer Matt Holyoak, show the Queen and Philip in the White Drawing Room at Windsor Castle in early November.
The royal couple are photographed against a platinum-textured back drop.
One shows the Queen beaming as she sits on a golden chair with matching upholstery with her hands resting on her lap, and the Duke standing next to her with his left hand in his pocket.
The 91-year-old monarch wears the cream day dress by Angela Kelly that she also wore at the Diamond Wedding Anniversary thanksgiving service, along with a yellow gold, ruby and diamond Scarab brooch, designed by Andrew Grima and given as a personal gift from Philip to the Queen in 1966.
In another of the portraits released on Sunday, Philip looks tenderly at his wife as they stand side by side, turned slightly towards each other, while a third image shows them standing next to each other, looking straight at the camera.
Another photo, issued on Saturday, shows the couple framed by Thomas Gainsborough’s 1781 portraits of George III and Queen Charlotte, who were married for 57 years.
The Queen holds her hands clasped in front of her, while Philip stands upright with his hands behind his back.
Mr Holyoak has worked with a host of celebrities and his photos have regularly been splashed on the covers of magazines such as Harper’s Bazaar, ShortList and Dazed and Confused.
The photographs were taken for Camera Press, which also celebrates its anniversary 70 years after the agency distributed the royal couple’s official wedding photos as its first assignment.
The enduring relationship of the Queen and the Duke has lasted the longest of any British sovereign, and Philip has been at the Queen’s side throughout the decades, supporting her as she devoted herself to her duties as head of state.
The Queen is the nation’s longest reigning sovereign, having overtaken the record set by Queen Victoria.
The 96-year-old newly-retired Duke, who was 26 and fresh from serving with the Royal Navy in the Second World War when he married, is the longest-serving consort in British history.
Together they have celebrated the Silver, Golden and Diamond Jubilees of the Queen’s reign, and faced ups and downs over the years including the breakdown of three of their four children’s marriages, and the backlash which followed the death of Diana, Princess of Wales.
With their family growing year by year, the Queen and Philip are preparing to welcome their sixth great-grandchild in April – a third child for the the Duke and Duchess of Cambridge.
They already have five great-grandchildren – Savannah and Isla Phillips, Mia Tindall, Prince George and Princess Charlotte, as well as eight grandchildren – Peter and Zara Phillips, the Duke of Cambridge, Prince Harry, Princess Beatrice, Princess Eugenie, Lady Louise Mountbatten-Windsor and Viscount Severn, and their own four children the Prince of Wales, the Princess Royal, the Duke of York and the Earl of Wessex.