For decades they have eyed each other warily across half a mile of crashing waves.

But while the Palace Pier has gone from strength to strength, its elder sister the West Pier has fallen into disrepair and spectacularly crumbled into the sea.

Now there are fears the grand old dame of Brighton could wreak a terrible revenge on her rival from beyond her watery grave.

Owners of the Palace Pier are worried timber and steel working its way free from the collapsed ruins of the West Pier could smash the foundations of their structure.

For the Brighton West Pier Trust there is an undeniable sense of something approaching poetic justice.

It blames the Palace Pier's owners for delaying essential repairs by lodging a European Court challenge to block a lottery restoration grant.

David Biesterfield, a director of the Noble Organisation which owns the Palace Pier, is calling for emergency demolition to prevent other vulnerable sections of the West Pier from adding to the sea-borne shrapnel.

He said the Palace Pier's piles were cast iron and very vulnerable to cracking if hit with heavy objects.

Dr Geoff Lockwood, chief executive of the Brighton West Pier Trust, insisted the West Pier's partial collapse would not have occurred but for the legal challenge, for which no date has been fixed.

He said the lack of emergency work meant sea-based parts of the pier were now uninsurable.

He said the trust would be liable for any damage caused to other property but the money in its coffers would probably not even cover the legal fees faced by any claimant, let alone compensation.

He said: "There are no plans to demolish the existing structure but the partial collapse will, we hope, expedite the implementation of the plans for its full restoration."

Mr Biesterfield said: "I am surprised and concerned at the suggestion that the collapse is in some perverse way our fault."