She is valuable because nearly 80 per cent of the 1945 structure still exists.

She still has both her main engines and boilers, the original hull and fire pumps, ballast pumps, all her steering gear equipment and even the original ship's gyro on the starboard side of the ship.

Malcolm Tattersall, head of the Maritime Steam Restoration Trust, is trying to save the Second World War ship from destruction.

He said: 'When you look at the design of her it's easy to see how she was the prototype for commercial roll-on, roll-off ferries.

'With Portsmouth being a major ferry port it is fitting that Stalker be saved.'

But fears were raised for the future of the vessel last month when the bow doors were cut off by contractors at the ship's site in Pounds Yard, Tipner, Portsmouth.

The Tipner Regeneration Company is responsible for the site and director Steve New said the work had been done to reduce injury risks to trespassers who clamber on the vessel.

Mr Tattersall, 54, said: 'Taking the doors off is extremely worrying because it threatens the integrity of the ship.

'We have been trying to save HMS Stalker for four years and we recently put in a bill of sale to show our intentions.

'We have also managed to get her on the register with the National Historic Ships Unit, which shows they think there is something worth keeping.'