"This is a precautionary measure to deploy them but it does not signal imminent military action."

Ministry of Defence source

The source told BBC News Online: "This is a precautionary measure to deploy them but it does not signal imminent military action."

Three rounds of talks have been held with the rebels over the past three days and on Monday the British military mission in Sierra Leone said negotiations were progressing well.

Senior officers are concerned the West Side Boys do not see the arrival of the Paras as a sign they are facing attack, which could put the hostages' lives in danger.

Unpredictable

The BBC's correspondent in Sierra Leone's capital Freetown, Allan Little, said as the unpredictable group would already know of the move British officials there were particularly keen to play down its significance.

He said negotiations are continuing but as usual no details were being given about the substance of talks.

Royal Irish Regiment troops were seized 11 days ago

The company from 1st Battalion Parachute Regiment is made up of the same men who were in Sierra Leone in May and they are familiar with the terrain.

Densely-wooded hills

The West Side Boys captured 11 Royal Irish Regiment troops in the densely-forested Occra Hills area, about 80km (50 miles) from the capital Freetown, on 25 August.

They are also holding one Sierra Leonean hostage.

The West Side Boys are not linked to the main rebel group, the RUF

Five of the soldiers were released on Wednesday.

It appears that the soldiers were taken hostage after becoming caught up in a local political dispute.

The West Side Boys, estimated to have a few hundred members, are an offshoot of forces loyal to the junta that ruled from May 1997 to February 1998.

However, many members are common criminals freed from prison when the militia took part in the rebel invasion of Freetown in January 1999.

The group split from the rebel Revolutionary United Front a year ago, declared allegiance to the government but after repeated clashes with government troops is now considered a renegade militia.

On Thursday, the militia broadcast demands on the BBC World Service, including the release of supporters and family, recognition by the Sierra Leone government and the establishment of an interim government.

The Sierra Leone Government has rejected their demands.