Two men from the Bradford district have been charged with conspiracy to supply drugs, following a major police investigation into the trafficking of large quantities of cocaine across Britain.

A 32-year-old man from Bradford and a 27-year-old man from Keighley were among six suspects, including a Colombian, quizzed by detectives in West Yorkshire in connection with the large-scale national conspiracy.

It is alleged that significant amounts of cocaine were being transported from the south of England into West Yorkshire.

The joint investigation, between West Yorkshire Police’s Crime Division and Thames Valley Police, began after £150,000 of cocaine was seized last August. A Peruvian from London has been jailed for eight years in connection with that find.

The latest arrests are part of a wider investigation, which is thought to extend to the international smuggling of cocaine into the UK.

West Yorkshire Police said six men were arrested yesterday in connection with a conspiracy to supply class A drugs. They were the two from Bradford and Keighley, along with four men, aged 35, 30, 29 and 21, from the London and Slough areas.

They were questioned by detectives at a police station in West Yorkshire. Last night, five of the men were charged with conspiracy to supply class A drugs. The other was bailed pending inquiries. Four of the men, including those from Bradford and Keighley, were due to appear before Leeds magistrates today. The fifth will appear next week.

Yesterday’s arrests came after 3kg of cocaine – with a street value of £150,000 – was seized from two suspects last August.

A 29-year-old Peruvian had travelled from his home in London to Leeds by train, and was stopped at Leeds railway station, where he was found to be in possession of almost 2kg of cocaine. He was convicted in January and jailed for eight years.

Later that month, a man, 32, from Sheffield was stopped in his vehicle in Birmingham by officers who recovered nearly a kilogramme of the drug. He was jailed for five and a half years in December.

Detective Inspector Noel Devine, of West Yorkshire Police’s Crime Division, said: “These arrests form part of a wider investigation, in conjunction with Thames Valley Police, into the supply of controlled drugs up and down the country.

“A significant amount of cocaine was found coming into West Yorkshire, believed to have originated from the south of England, and we are working hard to trace those responsible for bringing these drugs into our local communities.”

Detective Inspector Mark Sinclair, of the Serious and Organised Crime Unit of Thames Valley Police, said: “This is an excellent example of forces working together to tackle the problem of drugs in our communities.

“Two people have already been convicted in this case and we remain committed to catching those responsible for trafficking and supplying drugs.”