ABOUT 1,600 police officers backed by air and river support and Army specialists will be deployed in a massive security operation to protect Labour's Spring Conference in the region this weekend.

Northumbria Police yesterday revealed plans of the £2.8m operation designed to ensure the smooth running of the showpiece conference at The Sage in Gateshead, which will be attended by the Prime Minister and senior Cabinet members.

Assistant Chief Constable David Warcup also revealed that his officers had used the Terrorism Act to stop and search 170 vehicles on the region's roads over the past few days and had made four arrests, none of them connected with terrorism.

Last night, work was under way to cordon off the conference venue and nearby Hilton Hotel to create a secure island into which only delegates will be allowed access.

A specially-constructed footbridge over Bridge Street - paid for by the Labour Party - will allow delegates to cross from the hotel to the conference venue without encountering pedestrians.

The Swing Bridge, several roads leading into the area and the Tyne itself will be closed to traffic for the duration of the three-day conference, which starts on Friday.

The Tyne Bridge will be closed to pedestrians, which officers say is being done to prevent the landmark becoming a focus for protest.

Up to eight separate demonstrations are expected to take place during the conference - with groups as diverse as Fathers 4 Justice, the Stop The War Coalition and the pro-hunting Countryside Alliance all expected to converge on Tyneside to make their presence felt.

Police say demonstrators will be kept away across the Tyne at Wesley Square, on Newcastle's Quayside, although it had been agreed that a small number would be allowed through the cordon to petition delegates on their way into the venue.

Mr Warcup said that his officers had been negotiating with demonstrators for some time to ensure they could protest peacefully without disrupting the conference - but had contingency plans to extend the security cordon in the event of problems.

He said: "As far as the demonstrations go, we will be policing firmly, but fairly.

"Up to now we have had good co-operation but if they breach that trust they will be in breach of the law. We would have to act and we're in a position to do that."

Despite mounting criticism of the costs of policing the conference - and the disruption it is likely to cause to Tyneside - Mr Warcup said that he was confident the Home Office would ultimately foot the bill.

He added: "I am confident we can make it a safe conference - it won't be without its problems, but we are up to the task."