Thirteen people have been jailed for a total of 60 years after UK Customs broke up what it described as one of the biggest money laundering scams ever seen in Britain.

The operation funnelled profits of �50m from sales of cocaine in Britain to the Colombian drug cartels who supplied the drugs, mainly through high street bureaux de change.

The ring-leaders were from Colombia and Ecuador, but British people were also used in the operation.

Twelve of the 13 had been convicted before Monday, over the course of four different trials, but reporting restrictions had remained in place while the trial of the last defendant continued.

On Monday Juan Manuel Salgado, 50, a Colombian-born naturalised British citizen, pleaded guilty to laundering �2.3m and was sentenced to five years.

'Very professional'

The gang first aroused suspicions in 1998 when the National Criminal Intelligence Service began to receive reports of large amounts of notes being bought by several bureaux from currency wholesalers.

Customs then launched an undercover surveillance operation to follow the gang, who were described as "very, very professional" operators who had no contact with the cocaine itself.

Ian Watson, one of the customs officers heading the investigation, said the gang operated in two main ways:

• Sterling from cocaine sales was taken to certain bureaux de change and exchanged for dollars, which were then smuggled out of the country by couriers
  
• In a more complex operation, the same street cash was taken to the bureaux, passed into accounts, then electronically transferred to other accounts abroad

Salgado, of Beaconsfield Road in Ealing, west London, ran a bureau de change in Camden, north London, called Latin Linkup.

There, undercover officers saw "dirty" cash from the sale of more than 2,500 kilos of cocaine being changed into dollars to be taken back to Colombia.

�16m transactions

They saw Luis Edwardo Hurtado, 39, another Colombian-born naturalised British citizen, using a network of runners to collect money from drug traffickers.

They would take it to his World Express bureau de change in Camberwell, south London, where it was changed into dollars.

Hurtado pleaded guilty last year to laundering �13m, and is serving eight-and-a-half years in jail.

Others convicted included Chantana Platt, 55, a Thai-born naturalised British citizen, who ran the "7 Day Change" bureau in Bayswater Road, London.

Customs officers found a notebook in which she had recorded transactions with Hurtado totalling $16m (�10.8m).

Platt, of Bark Place, Bayswater, admitted her part in the scam and was sentenced to seven years.

Her niece, Pattama Potchapornkul, 28, also pleaded guilty to a part in the scam and was jailed for six months.

Stewardess 'mule'

In March 2000, Hurtado associates Benjamin Colorado, 41, and Ruben Dario Perez, 27, both Colombians, were seen changing pounds for dollars at a bureau de change called Rishtan Ltd near Victoria Arcade, central London.

Its owner, Indian-born Suresh Chopra, of Powys Lane, Palmers Green, north London, was later jailed for three years.

Undercover officers also watched Hurtado change �100,000 into dollars, and followed him and his business partner Mario Giraldo Lopez, 54, into a hotel.

Lopez went into a room with a rucksack and came out without it.

The room was rented by a Colombian air stewardess Yolanda Roa Jimenez, 50, who worked for the national airline Avianca.

She was later stopped at Heathrow before getting a flight to Bogota with $132,400 (�89,598) hidden in a false-bottomed bag, in her bra and in a torch.

Roa Jimenez and Lopez were each jailed for three years.

Profits chased

The gang was finally rounded up on 19 April 2000 when Hurtado left 7 Day Change with a bag containing �382,000 (�258,510).

Customs seized hundreds of thousands of pounds stored at various addresses, including a London flat belonging to Colombian John Serna Munera, 35, a Colombian national, which was being used as a counting house.

Munera was jailed for six-and-a-half years.

Hurtado's brother-in-law and "right-hand man" Byron Carrera, 34, an Ecuadorian, was also arrested and is serving six-and-a-half years.

Customs are now pursuing confiscation orders for the gang's profits.