Keir Starmer has come under further pressure to scrap the two-child benefit limit after another of his backbench MPs described the policy as “heinous”.
Writing in The Sunday Times, Canterbury MP Rosie Duffield said the cap, which came into effect under then-chancellor George Osborne in 2017, was “sinister and overtly sexist” and had been the main reason driving her to stand for parliament.
More than a dozen backbenchers are understood to support an amendment to the king’s speech.
The SNP has also tabled an amendment to scrap the limit, which prevents parents from claiming universal credit or child tax credit for a third child with a few exemptions.
Duffield said: “The obvious target is the caricature of the ‘feckless’, ‘irresponsible’ people who drop children every few minutes without being able to pay for them, but the subtext is altogether more sinister: it is an attack on women’s right to choose how many children they have.”
The MP criticised the so-called “rape clause” which provides an exception for children conceived through an attack, saying: “The authors of this policy are telling women: disclose to a series of total strangers that your third or any subsequent children are the result of rape and we will pay you after all.”
The UK government said there are 4 million children living in poverty, an increase of 700,000 since 2010.
The two-child benefit cap affects 1.6 million children, according to the latest figures from the Department for Work and Pensions.
Likening the policy to the dystopian society in Margaret Attwood’s novel The Handmaid’s Tale, in which women are deprived of their rights, Duffield said women were being “subjugated according to their social class”.
The new government has announced a taskforce to develop a child poverty strategy, led by Work and Pensions secretary Liz Kendall and education secretary Bridget Phillipson.
Many of the charities consulted by Kendall earlier in the week have also called for the cap to be abolished.
Ministers have previously suggested the state of the public finances means they cannot afford to abolish the cap.
The Commons leader, Lucy Powell, told MPs on Thursday: “As an incoming Labour government, we are absolutely committed to tackling child poverty and all the root causes of child poverty, which is why the prime minister announced the government taskforce looking at these matters yesterday.
“We were clear in our manifesto that the economic circumstances do not currently allow for us to abolish the cap.
“Economic stability is the single biggest thing we can do to ensure that children don’t fall into poverty, because when the economy crashes, it’s the poorest in society who pay the heaviest price.”