Boris Johnson married his fiancee, Carrie Symonds, in a private ceremony on Saturday morning UK time, becoming the first Prime Minister to marry in office for nearly 200 years.
Johnson, 56, and Symonds, 33, married at Westminster Cathedral, in central London, where their son, Wilfred, was baptised last year.
The ceremony came days after the couple were reported to have sent "save the dates" to family and friends for a celebration of their marriage on July 30, 2022.
Downing Street declined to comment on the ceremony. Some senior members of Johnson's staff were unaware of the wedding until after it had taken place.
A member of staff at the Catholic cathedral, which is around a mile from Downing Street, said they had only discovered the identity of the couple a day before the wedding.
Johnson and Symonds have been engaged since late 2019, but Johnson has repeatedly declined to comment on plans to marry. Asked in March whether he was planning a wedding later this year, he said: "The wedding industry is certainly going to come roaring back, in common with many other sectors of the economy."
The couple were married by Fr Daniel Humphreys, who had baptised Wilfred in a small ceremony in the cathedral's Lady Chapel last year.
One witness told The Sun that the cathedral was closed for half an hour while the ceremony took place. "It's not very often we have weddings here, and when they came out they were all bundled into a car," the witness said.
A member of staff said: "Yes, there was a wedding. It was the Prime Minister. Carrie looked beautiful. She had a long white dress with no veil. She looked made up. He was extremely happy, as you can imagine. He looked very smart and was in a very dapper suit.
"She came down the aisle and he didn't take his eyes off her. They read each other's vows and then they shared a kiss. They looked besotted."
Shortly before the ceremony, said to have lasted half an hour, Symonds posted a picture on Instagram of 1-year-old Wilfred in a field of bluebells.
Currently, up to 30 people can attend weddings as a result of a relaxation of Covid rules on May 17. The guests were said to have been invited at the 11th hour, such was the secrecy around the ceremony.
The cathedral was reportedly emptied of visitors shortly after 1.30pm, and half an hour later a limousine carrying Symonds drove into the piazza in front of the building. The bride stepped out of the car wearing a flowing white dress, and reportedly opted not to wear a veil.
Johnson and Symonds were said to have walked down the aisle to classical music and kissed after reading their vows.
One staff member said: "I was shocked when I heard who was getting married. It was kept very quiet. We only knew yesterday. Security has been tight. Police were everywhere. It was very planned."
Johnson met his first wife, Allegra Mostyn-Owen, while they were students at Oxford. They married in 1987, but the marriage was annulled in 1993.
Marina Wheeler and Johnson, who were both were pupils at the European School in Brussels, married in 1993 and separated in 2018. They have four children together: two daughters, Lara Lettice, 26, and Cassia Peaches, 22, and two sons Milo Arthur, 24, and Theodore Apollo, 20.
The Prime Minister has a fifth child, Stephanie Macintyre, with art consultant Helen Macintyre.
He has also previously been linked to the American entrepreneur Jennifer Arcuri and the journalist Petronella Wyatt.
Symonds, a former Conservative Party communications chief, was romantically linked to Johnson last year.
She joined the party's media department in 2009, first as a press adviser and then as head of broadcast, ahead of the 2015 general election.
She worked on Johnson's successful London Mayoral re-election bid at City Hall in 2012.
The couple had been living together at Symonds' flat in Camberwell, south London and now live in a flat above Number 11 Downing Street.
Symonds is credited with helping to redesign the flat as part of a refurbishment that has generated significant controversy.
On Friday it emerged Johnson told an official inquiry that he was unaware who paid the bill for the refurbishment.
A report by his ethics adviser found he acted "unwisely" by pursuing upgrades without knowing how they would be funded, but cleared him of breaking the ministerial code.
Lord Geidt, the Prime Minister's independent adviser on ministers' interests, revealed the work first began when Johnson was in hospital with Covid in early April last year.
Last night Arlene Foster, the First Minister of Northern Ireland wished the couple "huge congratulations" on their wedding.