The former Tory leader, who is heading a review on social justice for David Cameron, launched a blistering attack on big charities, claiming that they had become arms of government who rarely take risks. “They look over their shoulder at government the whole time because they are their source of funding,” he said.

He complained that there were few “believers” in big charities because they relied on paid staff rather than volunteers, and this helped to contribute to cynicism and “giving fatigue” amongst the public. “As Big Charity gets ever closer to Big Government, it increasingly mirrors its thinking and behaviour,” he said. “State bureaucracies feel threatened by new thinking and different approaches.”

He pointed to a recent poll commissioned by the Centre for Social Justice. This asked, “If you only had £200 to give to a good cause, who would you give it to?” Only 4 per cent opted for a national charity, he said, contrasting this with the 31 per cent who would give to a local charity or church working with needy people.

He singled out the NSPCC and Scope as examples of “bad” charities. Of the NSPCC, he said: “I can’t remember a single thing on the ground that the NSPCC have done.”

This has infuriated the charity, which accused Mr Duncan Smith of getting his facts wrong. A spokeswoman said: “Less than 10 per cent of our funding comes from government, we have 500 volunteers and we are not risk averse. There is no doubt about the independence of the organisation and we speak very strongly on behalf of children who have been abused.” She added that Mr Duncan Smith had spent a lot of time in Scotland, where the NSPCC did not operate.

A spokesman for the National Council for Voluntary Organisations also rejected Mr Duncan Smith’s theses. “You cannot apply the private sector model of ‘big is bad; small is good’ to the voluntary sector,” he said.

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