Anti-terrorist officers were today searching a cargo ship 30 miles off Beachy Head in what Scotland Yard described as a "major security operation".

They swooped on the MV Nisha at 8am along with the Royal Navy and Customs and Excise after an intelligence-led swoop.

British ships were waiting for the cargo ship when it arrived in the Channel.

Security sources said they were "acting on intelligence" that the vessel was carrying "terrorist material" but there was no specific intelligence that anthrax was involved.

A Scotland Yard spokesman said the ship was being inspected and the crew, thought to be Indian, was being interviewed and "co-operating fully".

The ship had sailed from Mauritius and was believed to be carrying a cargo of sugar, he said.

The Ministry of Defence said it was travelling west to east through the Channel.

There was no immediate danger to people living in the area, according to Scotland Yard.

The ship was boarded in international waters in accordance with international law, a police spokesman said.

The operation came just two days after eight suspected terrorists were rounded up under new anti-terrorism laws in London, Birmingham and Luton.

Suspects are still being held in high-security jails in London and Milton Keynes.