"We will now pursue anybody who has taken this money fraudulently. And I would urge anyone who's taken that money and didn't really need it to make contact with HMRC [Her Majesty's Revenue and Customs]. Anyone who thinks that they can escape the long arm of the HMRC is making a great mistake", Clarke told Britain's LBC Radio on Monday.
"Ignoring advice about fraud is bad enough, but for the chancellor to turn down support from the National Crime Agency is extraordinary", Reeves said.
"Fraud is totally unacceptable, and we're taking action on multiple fronts to crack down on anyone who has sought to exploit our schemes and bring them to justice", the spokesperson stressed.
The Liberal Democrats have, meanwhile, said that the government had "allowed fraudsters to steal billions of taxpayers' money", urging Chancellor Rishi Sunak to explain how he would get the money back.