G4S faces criminal probe after overcharging taxpayer millions for electronic tags Serco is not facing an SFO inquiry because it had agreed to allow auditors access to its files, as well as pulling out of current tendering competitions, the minister said. It also emerged that Ministry of Justice civil servants are facing disciplinary action because five years ago they failed to act on information which could have identified the scandal. Mr Grayling told MPs: "I am angry at what has happened and am determined to put it right. Overcharging for tagging began at least eight years ago and possibly dates back to 1999, he added. The revelation involving two of the government's largest private contractors placed Mr Grayling in an awkward position because his prison and probation reforms place a heavy emphasis on transferring work from the public sector to private firms. G4S and Serco have been barred from applying for any more government contracts until the completion of a series of reviews announced by Mr Grayling. The Cabinet Office will also scrutinize all existing contracts the companies hold across Whitehall. The full scale of the tagging scandal came to light after Mr Grayling brought in external auditors on May 17 after an internal review unearthed what he described as a "significant anomaly." The chief executive of G4S, Nick Buckles, quit his £1.2 million a year post on May 20. Mr Buckles had been criticised by MPs for "making it up as he went along" in the run-up to the Olympics. Mr Grayling said: "I should state that I have no information to confirm that dishonesty has taken place on the part of either supplier. Ashley Almanza, Mr Buckles" successor, said: "We are determined to deal with these issues in a prompt and appropriate manner." A Serco spokesman said the company would repay any amount agreed with the government. Spending on electronic tagging in England and Wales has run to £700 million since the two companies were handed the contracts by the previous Labour government in 2005.