After a four-year investigation, costing £16 million, the Serious Fraud Office (SFO) has said it does not intend to launch a criminal investigation into the collapse of MG Rover.

The announcement comes a month after the SFO was asked by Business Secretary Lord Mandelson to study the results of the independent report into the saga, which was commissioned by the former Department for Business, Innovation and Skills.

MG Rover collapsed in 2005 with the loss of 6,500 jobs after it was sold by BMW to the so-called Phoenix Four for £10.

In its first four years it made loses of £611 million before going into administration in 2005.

The four – Nick Stephenson, Peter Beale, John Towers and John Edwards – have always denied any wrongdoing.

The SFO said it could not comment further because the independent report had not been made public. It will be released on September 11.