According to customs investigators it was an anti-drugs smuggling operation "without parallel" in British history.

With the jailing of Hilton John Van Staden, one of the leading members of the gang, full details can now be revealed.

Spanning six years and more than half a dozen countries, Operation Extend has resulted in prison sentences totalling more than 200 years being handed down at five separate trials.

A vast and complex drug smuggling network was unmasked, which is estimated to have imported �360m of cocaine into the UK.

Operation Extend

Began September 1996 Led by UK Customs and Excise officers Visits made to Ireland, the Caribbean, USA, Mexico, Venezuela, Australia, France and S Africa Triggered second longest trial in UK criminal history Four specialist lawyers used for court cases

Yet the ring was only uncovered because a ship heading for the English Channel from the Caribbean went off course south of Ireland in September 1996.

The converted fishing trawler, named the Sea Mist, was subjected to a routine search when it docked at Cork and almost 600 kilos of cocaine was found on board.

Irish customs officers had stumbled on the tip of the iceberg.

The Sea Mist's crew were arrested and charged. As the scale of the organisation they were involved in emerged a huge surveillance and intelligence gathering operation was mounted.

The cocaine was destined for the gang's alleged 'Mr Big' in the UK, Brian Wright, a flamboyant businessman and a lover of gambling who is still at large.

Attention avoided

His home was an expensive villa in Spain, his residence of choice on frequent visits to the UK a rented luxury flat on the River Thames in London and his favourite day out a trip to Cheltenham races.

He was known as 'Uncle' and 'the milkman' to his fellow gang members, because in drugs trade parlance he always delivered.

But little did he know undercover officers had begun to follow his every move.

They found out that Wright's gang operated by shipping cocaine across the Atlantic in yachts and other vessels.

It was then transferred to locally-registered boats off the British coast to avoid unwanted attention when unloading.

Trusted friends

The supply network was based in Colombia, Mexico, Brazil and Panama and the ships were based in the Caribbean, Venezuela and South Africa.

Successful deliveries were completed between 1996 and 1999.

Brian Wright remains at large in Cyprus

All the individuals involved were relatives or trusted family friends.

They were disciplined and professional. They were aware of methods used by police and customs investigators and had access to fake passports.

But the first major blow was struck against the gang in February 1999 when, fearing key members were about to leave the UK, arrests were made and a quantity of cocaine seized.

Then, as officers prepared the resulting court cases over the next 15 months, more information emerged revealing the true scale of the operation they were investigating.

More individuals and their roles were identified, more vessels and crews were discovered.

Complex case

By the time of the first main trial in May 2000, other important members of the gang had been arrested.

Four specialist lawyers were taken on for the court cases due to the scale and complexity of the investigation.

Large numbers of witnesses and a huge array of evidence was used.

Maritime and metrological experts were brought in to assess the trips taken by the smugglers.

Seized address books with secret contact numbers and analysis of phone records revealed links between the gang members.

And hours of surveillance evidence was also used to back up the cases.

Officers delighted

Up to now 15 members of the gang - British, Brazilians and Columbians - have been convicted or have pleaded guilty to a variety of drug related offences.

What Customs and Excise believe is the most prolific and successful drugs gang ever has been smashed.

The organisation's officers are delighted with the success they have had.

The gang may only have been one part of the vast smuggling trade into Britain but it has provided an invaluable snapshot of how such a huge, sophisticated network operates.

However, the satisfaction felt by investigators is tempered by the knowledge that the alleged ringleader is currently free and living in northern Cyprus.

With no extradition treaty in place with Britain, Brian Wright remains out of reach of British justice - for now.