Stella Creasy, an opposition Labour lawmaker, has campaigned for MPs to be offered full maternity cover.
A British MP won a promise of parliamentary reforms on Wednesday after she was rebuked by an official for bringing her sleeping baby to a debate.
Stella Creasy, an opposition Labour lawmaker who has campaigned for MPs to be offered full maternity cover, received the warning after speaking at a debate on Tuesday while holding her three-month-old son Pip.
The London MP tweeted an email from an official at the House of Commons citing a rule that "you should not take your seat in the chamber when accompanied by a child".
"Mothers in the mother of all parliaments are not to be seen or heard it seems," Creasy complained.
Her treatment prompted anger from MPs on all sides and promises of a review of the current rules, which officials admitted had been applied inconsistently.
The Speaker of the House of Commons, Lindsay Hoyle, told MPs that he had not known of the official's rebuke.
But he stressed: "It is extremely important that parents of babies and young children are able to participate fully in the work of this House."
Creasy said she was "pleased to hear this".
Conservative Prime Minister Boris Johnson, whose wife Carrie is expecting their second child, backs reforms but the decision is up to the House of Commons, according to his official spokesman.
"We want the workplace in any circumstances to be modern and flexible and fit for the 21st century," the spokesman said.
Justice Secretary Dominic Raab, who also has young children, expressed support for Creasy.
"Quite what the right balance is in terms of the chamber, let me leave that to the House authorities, but frankly I've got a lot of sympathy for Stella Creasy," he told BBC television.
"I think we do need to make sure our profession is brought into the modern world, the 21st century, and can allow parents to juggle the jobs they do with the family time that they need."'Mums can't win'
Despite the formal ban, MPs have previously brought babies to debates without reprimand. Former Liberal Democrat leader Jo Swinson was the first to do so in 2018.
Alex Davies-Jones, a Labour MP, tweeted that when elected in 2019 she was breastfeeding and Hoyle assured her she would be able to feed her baby in the House of Commons itself or Westminster Hall, an adjacent historic building that is used for less significant debates.
Creasy is still breastfeeding Pip, and had previously brought her baby daughter to parliament.
"He's very tiny" and "perhaps some of my colleagues are noisier than him", she told Sky News, calling for a more flexible approach from parliamentary authorities.
"It's a part and parcel of modern life, isn't it, that sometimes you might need to have your children with you."
Creasy has campaigned unsuccessfully for MPs to get full rights to maternity cover.
"When you're a mum you can't win," she added.
The government in February introduced six-month formal paid maternity leave for senior ministers. Attorney-General Suella Braverman was the first cabinet member to benefit from the new law.
But the rules for backbench MPs are different. Creasy in 2019 became the first MP to hire a locum to work on her behalf after her daughter's birth, but was not allowed to do this again for Pip.