Police were originally called in to investigate the now defunct South Yorkshire Trading Standards Unit in January 2006 following the death of its manager Mike Buckley. A routine internal audit carried out after he died of a heart attack uncovered a £7m black hole in the unit's finances.

Investigations into Mr Buckley's activities revealed substantial irregularities in the finances, which ultimately caused the closure of the unit in August 2006 and the loss of 24 jobs.

The three men charged are Paul David Liggins, 54, from Northampton, David John Abbott, 60, from Sheffield, and William Charles Whitehead, 62, of Chesterfield.

They will appear before Sheffield Magistrates' Court on September 30, where it is likely the case will be transferred to the Crown Court for trial.

The men all face one count of conspiracy to false accounting. Mr Buckley has been named as an alleged co-conspirator.

None of the men worked at the trading standards unit but were agents involved in providing services to the unit through their own external companies.

The companies are Precise Exports Ltd, owned by Mr Liggins; Metrology Support Services Ltd, owned by Mr Abbott; and, Calibration Logistics Ltd and North Derbyshire Measurement Systems Ltd, both owned by Mr Whitehead.

Before his death in December 2005, Mr Buckley's financial figures appeared to show that the department was making a modest annual profit. But further investigations in 2006 revealed that it had been losing millions of pounds for an untold length of time.

Mr Buckley had managed the unit in Chapeltown, Sheffield, for 30 years.

It was said that he covered up the fact that the unit's income was far below its spending for many years, undetected by auditors.

The unit had been operated by four local authorities – Sheffield, Barnsley, Rotherham, and Doncaster councils. After the unit was closed, the land and the highly specialised equipment used by its staff was sold in a bid to recoup some of the lost money.

However, the four councils still had to find around £14m, due to an equipment leasing agreement, in order to cover the deficit caused by the financial deceit.

The loss was shared by the four authorities based on their populations. Rotherham, Barnsley and Doncaster paid more than £2m each, while Sheffield was left with a bill for around £5.8m.

The SFO has investigated the case in partnership with South Yorkshire Police, who said they could not comment on the inquiry.

Alan May, the lawyer in charge of the investigation for the SFO, said: "The SFO is pleased to have issued proceedings and is keen to get this case to the Crown Court as soon as possible so we can take it forward."

A spokesman for the four South Yorkshire authorities said: "We are pleased that the investigation has resulted in these charges. Anyone who has participated in dishonest activity involving public money should be brought to account."