The Labour MP for north west Durham has asked Theresa May whether the rollout of Universal Credit is a matter of "gross incompetence or calculated cruelty", as Labour MPs applied further pressure on welfare reform.
Laura Pidcock was among those to raise the issue at Prime Minister's Questions, as the Government prepares to face a Labour-led debate on the benefit in the Commons.
The Prime Minister said the Department for Work and Pensions (DWP) was listening to concerns and improvements were being made to the system, which rolls a number of benefits into a single payment.
Mrs May replied: "The DWP has been rolling out Universal Credit. As it has done so, it has been listening to people about the concerns that have been raised.
"I'm pleased to say that we are seeing a much better performance from the DWP.
"It's no good (Ms Pidcock) shaking her head - the figures show that the performance in terms of getting payments to people on time has increased substantially, more people are getting advance payments, and we want to ensure all those who need those advance payments are indeed able to get those payments.
"But the fundamental reason for moving to Universal Credit, of a simpler system, a more straightforward...she may not want to listen to this, but there is a reason for Universal Credit."