OK then, here are some figures to the picture, to give a sense of perspective. Here goes ...
Benefit fraud is £1.1bn (figure from the Treasury).
Tax Credit Fraud is £0.49bn, not the £5.2bn as claimed by Cameron recently. He has since revised his figures, but £5.2bn is what the tabloids have been reporting. (The larger figure included overpayment due to clerical error, not just fraud).
The Child Poverty Action Group (CPAG) has stated that benefit fraud is at an all-time low and that administrative problems and low take-up meant that in fact an estimated £16bn of legitimate benefits remained unclaimed.
CPAG policy and research officer Gabrielle Preston said the proposal to bring in outside agencies added to the already intense stigma.
"While we recognise there is a need to minimise benefit fraud, it is currently at an all-time low - less than 1 per cent of claims," she said.
"The system's complexity means £16bn is unclaimed by some of society's most vulnerable people.
"This initiative stigmatises the most vulnerable people and is likely to further reduce take up of much-needed benefits and tax credits."
"If the government is to meet its 2020 commitment to end child poverty, it must protect children whose parents are entitled to receive benefits and tax credits.
"It is unacceptable for politicians to inflame stigma and discrimination against some of the most vulnerable people in the country.
"The coalition should take a lead in challenging myths about people who rely on the welfare system."
According to the Treasurys own figures, £40bn a year is lost in high-level tax avoidance and evasion. Thats enough to pay for the entire Building Schools for the Future programme. It is also far more than the cost of income support, disability benefit and jobseekers allowance combined.
Tax Justice Network director John Christensen said: "Data from independent sources suggests that the cost of tax evasion and avoidance in the UK outweighs benefit fraud by at least fifteen to one.
"Both problems involve theft of public property, but the government remains soft on tackling evasion because in the majority of cases it involves rich people and powerful companies. The favourable treatment offered to tax evaders is socially corrosive."
The use of the private sector in the detection of benefit fraud is an example of conservative policy based upon ideology, being portrayed as efficiency and cost cutting. The public service has been getting better at routing out benefit fraud, so why involve a private company?!