The risk of a terrorist attack on this year's Labour Party conference is rated as low, police chiefs said today.

The conference is being held at the Brighton Centre from September 27 to October 1 with around 13,000 delegates and their staff expected to descend on the city.

Preparations for the conference, codenamed Operation Otter by Sussex Police, have been under way by a dedicated team of officers for the past nine months.

Speaking at a press conference at Brighton Police station today, Superintendent Grenville Wilson said the force was confident there would be no major disruptions to the event.

Referring to the current national terror threat of substantial, he said: "For the conference itself that actual assessment is reduced to low, an attack is unlikely.

"That is predicated on all the preparation we have been doing. We aim to make it very, very difficult for anyone thinking of coming in and committing crime towards the conference because of the various measures that are taking place."

During the conference, police will seal off the area around the Brighton Centre and the surrounding hotels that are also being used to form a secure "island site".

Officers have already visited up to 1,000 people living in the immediate area to carry out checks on who they are while armed police will patrol the area once the event begins and anti-vehicle barriers will be erected around the site.

Mr Wilson said the force was already well-rehearsed in policing on such a scale as it is the sixth time the Labour Party conference is being held in Brighton since 1997.

Around 1,000 police officers and support staff will be involved in the operation on a daily basis, with specialist officers from other forces around the country also being drafted in.

The operation is expected to cost £5.7 million, which will be funded by the Home Office.

Mr Wilson said Sussex Police had been in touch with a number of groups expected to conduct protests during the conference.

He added: "I would actively encourage anybody who wishes to do so to contact us about that."