Czech police foil huge sale of Semtex

The Czech police revealed yesterday that they had made one of their biggest seizures of the terrorists' favourite explosive, Semtex, at a filling station on the Prague-Brno motorway in April.

About 33kg (73lb) was found: enough to level a building 10 to 15 storeys high, the police said. The announcement was delayed to facilitate investigations, they added.

The Czech Republic has been under pressure from Nato and the US to prevent Semtex falling into the hands of terrorists. The explosive, which was used in the Pan Am jet which exploded over Lockerbie in 1988, is hard to detect and can be taken through security controls with relative ease.

The police said two men and a woman were arrested for trying to sell the Semtex, 267 electric detonators and 150g of the highly flammable and slightly radioactive chemical rubidium.

The police gave no indication of where the explosive may have been going. Semtex is used extensively in industry and construction and by the armed forces.

It usually reaches the black market by being stolen and passed to an intermediary. Often the thieves have no idea where it will go. Its users include organised criminals as well as terrorists.

Czech state radio said the three people arrested were trying to sell the materials for 1.4m crowns (£30,000). On the black market abroad, Semtex sells for up to£850 a kilo.

Earlier this year the Czech government took control of Explosia, the manufacturer of Semtex and other explosives, in order to tighten security.