Protesters fighting plans to restore Brighton's crumbling West Pier are trying to destroy the landmark structure, it has been claimed.

The West Pier Trust, leading plans for a £30 million renovation of the Grade I listed pier made the allegations after the second fire in as many months damaged what is left of the 137-year-old attraction.

A security guard, employed after a massive blaze in March destroyed the pier's pavilion, spotted smoke coming from the already collapsed concert hall.

Police and fire chiefs said there was no firm evidence to suggest the fire was deliberate but the Trust is adamant.

General manager Rachel Clark said the fire was arson and deliberately timed to coincide with the imminent dismantling of the concert hall at the promenade end of the pier.

She said someone was trying to "scupper" the renovation project, but had succeeded in strengthening the Trust's resolve.

"This was a professional job and it will make us more vigilant but I am sure there will be another attempt, if not tonight then soon."

Ms Clark said the Trust was concerned that the fire in March had left people in doubt over the pier's future.

She said: "We are concerned that people think the plans are off but the project is still very much alive. There will be activity at the pier in the next few weeks and that will help to boost the profile of the plans."

Police refused to comment if the fire was the work of arsonists but said they had received reports of fireworks being let off in the vicinity of the pier last night.

A Sussex Police spokesman said: "The forensic side of the fire has been considered but the pier is in such a bad state that if there is any evidence it is now likely to be at the bottom of the Channel."