Armed officers patrol Brighton city centre as part of conference security

Last-minute checks were made on Saturday in the �3.7m operation, which saw a "secure island site" established round the Brighton Centre on Friday.

The neighbouring Grand Hotel and Hilton Metropole are included in the seafront ring of steel, and concrete slabs have been laid to prevent terrorist attacks.

Sussex Police said conference security was reviewed after July's London bombs.

The concrete slabs around the island site are intended to prevent attacks such as truck or car bombs.

"There are some extra measures we have taken which won't be visible, and I am absolutely confident that Brighton is going to be a very safe place during the conference," said Chief Supt Jeremy Paine.

Armed checkpoints have also been set up at various points leading into the city.

Police are 'confident' the conference will be able to go ahead

Delegates including Prime Minister Tony Blair arrived on Saturday for the conference, which gets under way on Sunday.

They will face rigorous bag searches and checks of their credentials.

Everything entering the venue - right down to the bottled water - has been X-rayed.

Royal Navy ships are expected to patrol the shoreline, while an air exclusion zone will be in force over the city centre.

Motorists have been warned to expect traffic delays and vehicle passes will be necessary for anyone wanting to enter the island site and the area to the north.

Brighton and Hove City Council said delegates bring about �10m to local businesses.

"This event helps us win other conferences, which cause no disruption," said deputy council leader Sue John.

Vehicle passes will be needed by people entering the secure area

"Our competitors would dearly like to take all this business from us and the jobs it brings but it's very important it remains in the city."

Manager of Churchill Square shopping centre, Derek Maddison, said the Labour Party Conference did put shoppers off.

"It does affect the number of visitors into the shopping centre for that period," he said.

"But it puts money into people's pockets and we get it spent the next week and before Christmas."

Thousands of local people will use the conference to draw government attention to issues affecting them.

On Sunday, supporters of Brighton law student Omar Deghayes, imprisoned in Guantanamo Bay, are to protest outside the conference and Sussex Action for Peace will hold an anti-war demonstration.

On Monday, thousands of Brighton and Hove Albion supporters are to march in support of a new football stadium at Falmer, on the outskirts of the city.