The BBC's Rory Cellan-Jones: Firm found guilty of a catalogue of errors

The firm has been fined £1.2m and ordered to pay an additional £2.2m in costs for its role in the collapse of Mr Maxwell's business empire.

It is the largest fine ever levied under the accountancy profession's Joint Disciplinary Tribunal.

Accountants 'lost the plot'

The company, which has paid the fine, did not contest the charges against it.

Senior partner Peter Smith said their failings were a matter of deep regret:

"We accept that we fell short of the very high standards we set ourselves. As soon as it became clear what had happened, we said the first priority for everyone must be the welfare and long-term security of the pensioners."

After the death of Mr Maxwell, who owned the Mirror Group newspaper, it emerged that pension funds intended for former staff had been invested in other Maxwell companies to try to prop up their share price.

The Maxwell empire collapsed in 1991 leaving its pension funds £400m in deficit.

Coopers & Lybrand, now merged with Price Waterhouse, was a long-term adviser to Mr Maxwell. The firm acted as auditors of nearly all the Maxwell-controlled companies and their pension funds from 1972 onwards.

Firm 'lost the plot'

The long-awaited report from the tribunal said Coopers & Lybrand had "lost the plot."

It said the firm had failed to consider whether there was "evidence of fraud, other irregularities, defaults or unlawful acts" at Mr Maxwell's businesses that would merit "whistleblowing" to the proper authorities.

"The complaints reveal shortcomings in both vigilance and diligence and a failure to achieve an appropriate degree of objectivity and scepticism, which might have led to an earlier recognition and exposure of the reality of what was occurring," it added.