TaxPayers' Alliance political director Jonathan Isaby says the principle of simplifying the benefits system is right but the implementation is "deeply flawed".
He added: "A horrendous amount of taxpayers' money has already been wasted and those responsible for that must be held to account.
"Such a fundamental reform of the welfare system was always going to be a challenge, but the approach of many officials in the Department for Work and Pensions has been little short of shambolic."
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