The Labour MP Stella Creasy has asked for urgent clarification from Commons authorities after being reprimanded for having her infant son in a sling as she spoke in parliament on Tuesday, saying this had not been a problem on other occasions. While Commons rules state that MPs should not have children or infants with them in the chamber, Creasy has taken both her children into the Commons before, without any complaints being made. The Walthamstow MP led a debate about buy-now-pay-later consumer credit schemes on Tuesday afternoon in Westminster Hall, a subsidiary chamber where MPs can raise issues of interest to them. She later tweeted an email she had received from Commons authorities. “We have been made aware that you were accompanied by your baby in Westminster Hall earlier today,” it read, from the private secretary to the chairman of ways and means, which is the formal title for the most senior deputy speaker, currently the Conservative MP Eleanor Laing. The email pointed out that the latest edition of rules of behaviour and courtesies in the House of Commons, the handbook for MPs, says they should not take their seat in the Commons while with a child, adding: “I would like to draw your attention to the fact that this also applies to debates in Westminster Hall.” This edition of the rules, published in September, states that MPs can take babies or toddlers with them through the lobbies to vote, and if needed through the Commons to do so, but adds: “You should not take your seat in the Chamber when accompanied by your child, nor stand at either end of the Chamber, between divisions.” The same wording was also in the previous version of the rules. However, Creasy has taken her children into the Commons before without reprimand. On 23 September, with her then-newborn son in a sling, she asked Jacob Rees-Mogg, the Commons leader, if he would consider revising other rules which mean that MPs on parental leave must give up the proxy vote they are permitted if they want to speak occasionally in the chamber. Rees-Mogg defended the rules, but told Creasy he wanted to “congratulate her on the impeccable behaviour of her infant”. After Creasy’s tweet another Labour MP, Alex Davies-Jones, tweeted that the rule seemed “a complete contradiction” given that when she was breastfeeding her child the Commons speaker, Lindsay Hoyle, assured her “that if the need arose I would be able to feed my child in the chamber or Westminster Hall”. Creasy, who also has a young daughter, has battled to ensure MPs can have proper maternity cover, but without success so far. She has tussled with the Independent Parliamentary Standards Authority to get a locum paid near to her own salary rate to cover her constituency casework. The law prevents a locum from being able to cover the parliamentary work of MPs on parental leave. More recently, Creasy launched a campaign called This Mum Votes – originally named Vote Mama UK, after an existing US campaign – to help support parents in politics, saying she did not think her own party had properly backed her push for maternity rights. Creasy, who says she has been assured the email was not prompted by a complaint from an MP, told the Guardian she was baffled by what had happened. “Without maternity cover, the residents of Walthamstow would be denied representation if I didn’t keep working – but anyone with a three-month-old baby knows they are too young to leave on their own,” she said. “Having already taken my baby into the chamber previously without any complaint, I‘ve asked for urgent clarification as to what would happen if I keep bringing the baby with me, and where they expect me to leave him – issues like this are why we have set up the This Mum Votes project so we can ensure that the mother of all parliaments ensured mothers can be seen and heard in our politics.”