Operation Steeler, as it was known, involved up to 100 officers and ended with the seizure of six containers filled with drugs on Pevensey Bay beach, East Sussex, and the capture of a catamaran.

No one has been convicted for smuggling �34m of cocaine into the country

Togher, 34, from Bellshill in Lanarkshire, and Doran, 53, from Glasgow, were sentenced to 25 years at their second trial in 1997 for smuggling 300 kilos of cocaine.

But the men were cleared by the Court of Appeal, which ruled Judge John Foley had misled the court during his summing up of the UK's longest trial.

Charges against the men were dropped altogether when a retrial heard customs officers had planted bugging devices at the luxury Swallow and Lanesborough Hotels in central London without permission.

Lack of resources

Judge Butler, in his report released on Thursday, said he thought that decision had been wrong.

"I know customs would have welcomed the opportunity to put their case in front of the Court of Appeal and say the trial should not have been stopped," he said.

He identified widespread failings in the customs operation.

"The solicitors department at the customs is simply not sufficiently resourced and I somehow doubt it ever will be," Judge Butler said.

He said the investigators had never intended to deceive the court, or act improperly without official authorisation.

"These officers I saw I would describe as hard working and dedicated...for the kind of pay most lawyers would describe as derisory," he said.

"They deserve a little encouragement not constant criticism."

Mistakes 'will not be repeated'

Judge Butler recommended using judges in large and complex drug cases from a limited pool, as they are for complex fraud cases.

He said prosecutors should also be given the power to challenge a judge's decision on whether a trial should go ahead, a matter currently being considered by the Law Commission, which advises the government on legal matters.

But new regulations introduced since the trials mean similar mistakes are unlikely to occur again.

"I am talking historically here," he said.

"What took place really could not, I would have thought, happen again given the laws now in place."