Boris Johnson and Carrie Symonds reveal name of their baby boy
Ms Symonds, 32, posted a picture of her cradling the newborn on Instagram on Saturday, saying she "couldn't be happier" and that her "heart is full".She praised the maternity team at University College Hospital in London, who she said "looked after us so well".
Ms Symonds and Wilfred are understood to be back in Number 10 with Mr Johnson.
The couple announced on Wednesday that she had given birth to a baby boy earlier that day.
It came just weeks after Mr Johnson was discharged from intensive care where he had been battling coronavirus. Ms Symonds also suffered symptoms of the disease.
She wrote in her Instagram post: "Introducing Wilfred Lawrie Nicholas Johnson born on 29.04.20 at 9am.
"Wilfred after Boris' grandfather, Lawrie after my grandfather, Nicholas after Dr Nick Price and Dr Nick Hart - the two doctors that saved Boris' life last month.
"Thank you so, so much to the incredible NHS maternity team at UCLH that looked after us so well. I couldn't be happier. My heart is full."
Mr Johnson, who is currently grappling with the Covid-19 crisis, is expected to take a "short period" of paternity leave later in the year.
The new family are planning to live in their Downing Street flat along with their dog Dilyn, Downing Street has said.
The baby's first name is a tribute to Mr Johnson's paternal grandfather, Osman Wilfred Kemal, later Johnson, whose father, an interior minister of the Ottoman Empire, was killed in the 1922 Turkish War of Independence. His mother, Winifred, died in childbirth.
Professor Marcel Levi, chief executive of University College London Hospital, congratulated the couple on the birth of their son.
He added: "I would like to thank the teams who cared for Carrie and her baby. They are an incredibly skilled, dedicated and compassionate group of professionals who put patients at the heart of everything they do.
"I am very proud of them and all our staff at UCLH who are working extremely hard in very difficult circumstances at the moment." ?
In February, the couple announced they were expecting a baby in "early summer" and that they had become engaged at the end of 2019.
They made history as the first unmarried couple to officially live together in Downing Street when they moved in last summer, after Mr Johnson won the Conservative Party leadership contest.
The new arrival is the third baby born to a serving prime minister in recent history.
Tony Blair's wife Cherie gave birth to son Leo in May 2000, three years after her husband's first election victory.
David Cameron and wife Samantha welcomed daughter Florence in 2010.
The last babies born to prime ministers before Leo and Florence arrived more than 150 years ago.
Wilfred is Ms Symonds's first child, while Mr Johnson is known to have fathered five others.
His four children from his previous marriage to the lawyer Marina Wheeler are called Theodore Apollo Johnson, Lara Lettice Johnson, Cassia Peaches Johnson and Milo Arthur Johnson.
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