The Serious Fraud Office has dropped its inquiry into the collapse of car maker MG Rover.

The decision not to pursue a criminal investigation paves the way for the publication of a four-year independent report into the collapse.

The Serious Fraud Office (SFO) said it reached its decision after a team of investigators looked into the inspectors' report but it was unable to go into detail as the report has not yet been made public.

A spokesman said: "The Serious Fraud Office has announced that it does not intend to begin a criminal investigation into the sale of car manufacturer MG Rover Group, following a review of documents sent by the Department of Business, Innovation and Skills.

"A report on the circumstances surrounding the sale of the MG Rover group, which was compiled by independent inspectors appointed by the Department of Trade and Industry, was referred on to the SFO on July 6 by the Secretary of State for Business, Innovation and Skills, Lord Mandelson, after he studied the findings. The inspectors delivered their report on June 11."

He said a small team of investigators studied the report and made recommendations to the SFO's director, Richard Alderman, who took advice from lawyers. "As the inspectors' report has not been made public, the SFO is unable to go into detail about the reasons for its decision," he said.

The Birmingham-based car maker collapsed in April 2005 with the loss of 6,000 jobs.

The four executives in charge - John Towers, Nick Stephenson, Peter Beale and John Edwards - have always denied any wrongdoing.

But the so-called Phoenix Four came in for much criticism when it was revealed they had taken out an estimated £40m in pay and pensions in the five years they controlled the firm. Former Rover executive Mr Towers paid a nominal £10 for the firm in May 2000 when his Phoenix consortium took over the company from BMW.

The four-year independent report looked into what went wrong between Phoenix Venture's acquisition of the firm and administrators being brought in.