The wreck of the first British-made submarine is in Dire straits at the bottom of the Solent, according to a new report.
English Heritage says the A1, built in 1903 and sunk twice with the loss of 11 submariners by 1911, is in 'significant decline'.
Divers have been blamed for speeding up the natural decay of the historic vessel by visiting the site and taking items away with them.
The English Heritage 'At Risk Register' also lists Gosport Railway Station and nine other sites in the area as badly needing help to prevent them falling into disrepair.
The Vickers-built A1 lies two miles south of Chichester harbour and is in such a poor condition naval experts fear for her future.
George Malcolmson, archivist at the Royal Navy Submarine Museum in Gosport, said: 'It stands to reason that if the wreck is lying under the sea it will rust, but there have been other problems with her.