Margaret Thatcher is escorted from the Grand Hotel after the 1984 blast

More than 1,000 police will take part in Operation Otter in and around the Brighton Centre providing security for ministers and delegates at the event.

Police say there is no specific information about a threat.

Chief Superintendent Jeremy Paine said: "Brighton will be a very safe place to be during the conference."

He added: "There is no information that anyone is interested in targeting the conference," he said.

"However, if something does become known, we will be ready for it. We have in place a no compromise approach to security."

Island of security?

Pontoon shaped barriers made of steel and encased in concrete will be placed around a sealed site that will include two hotels and the conference centre.

Chief Supt Paine said: "The barriers will make sure no vehicle can be driven into island site, either accidentally or on purpose."

The Metropole and the Grand hotels will be connected to the conference centre by a specially constructed bridge.

The adjacent multi-storey will be shut to members of the public and searches of the surrounding car parks conducted.

Cash injection

Special stop and powers will be introduced before and during the conference and police will be able to close all roads in the city at short notice should a security threat emerge.

Grand Hotel, Brighton after the bomb attack

An air exclusion zone will be enforced but there will be no sea exclusion zone.

A spokesman for Brighton and Hove Council said the event would mean �10 to �15m for the local economy.

"Sometimes it is difficult for people to understand why this conference is important to us, but we want to emphasise that we welcome the event into our city," the spokesman added.

Labour's conference comes nearly 20 years to the day after the IRA launched a deadly attack on Margaret Thatcher's government at the Grand Hotel in Brighton killing five people.