On Wednesday 29 April, it was announced that Ms Symonds had given birth to a baby boy in the early hours of the morning.
A spokesperson for the prime minister and his fiancée said: “The Prime Minister and Ms Symonds are thrilled to announce the birth of a healthy baby boy at a London hospital earlier this morning. Both mother and baby are doing very well.
“The PM and Ms Symonds would like to thank the fantastic NHS maternity team.”
Following the announcement of the new addition to their family, Mr Johnson and Ms Symonds have received numerous messages of congratulations, including from former prime minister David Cameron, London mayor Sadiq Khan and Labour leader Sir Keir Starmer.
They have also been sent well-wishes by the monarch, Buckingham Palace revealed.
The Palace stated that the Queen has sent Mr Johnson and Ms Symonds a private message to congratulate them on the arrival of their baby boy.
Downing Street has confirmed that the prime minister will take paternity leave by the end of June.
No 10 said Mr Johnson intends to take time off “later in the year, rather than now”.
Official rules dictate that paternity leave of one or two weeks “cannot start before the birth (and) must end within 56 days of the birth”.
This means that unless the rules are changed for the prime minister, he would have to take his paternity leave by 23 June.
The birth of Mr Johnson and Ms Symonds’ baby coincides with the wedding anniversary of the Duke and Duchess of Cambridge.
On this day in 2011, Prince William and Kate were married in a lavish ceremony held at Westminster Abbey in London.
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