Police are investigating claims the West Pier fire was started as a protest against the war in Iraq.

The Argus yesterday received a letter from the alleged arsonist, detailing how he got on to the pier and started the blaze.

The pier's famous pavilion burned down on Friday last week.

The author, signing himself as Piers Burns, said the fire was started on the first-floor of the old theatre on a pile of timber.

The letter stated: "I spread five litres of petrol over the timber. The fire was started using a delay fuse. It did not threaten human life or other property. It was done in anger, a protest at the US/UK invasion of Iraq.

"It was done to highlight the incongruity between saving the West Pier and bombing Baghdad.

"The pier was a good target because, like with Iraq, it is being exploited by hypocrites with the collusion of the council and media, intent on personal gain."

Police think the timing of the claim throws doubt on its authenticity: Why wait a week when media coverage of the fire was at its height last weekend?

How did the author carry five litres of fuel while swimming out to the fallen gangway where he gained access?

The West Pier Trust and its engineers said details given by the author of how and where the fire started and how access was gained, lent credibility to the claim.

A Brighton and Hove CID spokesman said: "We are investigating the claim but at this stage we are keeping an open mind about its authenticity."

Dr Geoff Lockwood, chief executive of the Brighton West Pier Trust, said more would have to be spent on security.