The world's most wanted man, Osama Bin Laden, paid $30m to have four British telco engineers beheaded in Chechnya, BBC's The Money Programme will reveal tomorrow.

The broadcast, entitled 'Kidnapped' and due to be shown on BBC2 at 7.30pm on Wednesday, shows that Bin Laden paid the blood money to the Islamic fundamentalist warlord, Arbi Barayev, who dealt with the terrorist through an Arab called Kattab.

According to Western intelligence sources, Kattab had been paid millions of dollars by Bin Laden to foment Islamic revolution in Chechnya.

Barayev, who had already amassed a personal fortune through kidnapping, snatched the engineers - Rudi Petschi, Peter Kennedy, Stan Shaw and Darren Hickey - from Chechnya's capital, Grozny. They had been working in the former Soviet Republic for UK firm Granger Telecom to repair the telecommunications infrastructure that had been ravaged by a two-year bloody war with Russia.

The technicians were beheaded some time between the 5th and 8th of December 1998, despite successful ransom negotiations.

The Money Programme unearthed Bin Laden's involvement by tracking down another Barayev hostage, Abdurakhman Adukhov, who was held with the engineers but later released. He told BBC investigators that he personally spoke to Barayev and asked him why he'd killed the Westerners.

The programme quoted Adukhov saying that Bin Laden offered the warlord $30m, whereas the ransom to return the men alive was only $10m. "According to Barayev, his Islamic faction would be paid more money if they murdered the men rather than freed them. The money would come from Arab friends."

"It seems the money may have been part of a wider package to spread Islamic fundamentalism in the region so that Westerners would be scared away. Bin Laden and his allies would be given a freer hand," the programme added.

The BBC also interviewed another man kidnapped by the gang, Shak Sharukhanov, who confirmed that the decision to murder the Granger Telecom employees was made while ransom negotiations were still in progress.

The Foreign Office said it is currently investigating the information exposed by the BBC investigation.