With armour-plated walls rising defiantly from the sea, No Man's Land Fort has held out against invaders since it was built to repel Napoleon III 150 years ago.

Now, however, the Solent fortress is under siege for the first time and could be facing its most determined enemy yet - estate agents. The fort, which has been converted into a hotel, has been put on the market by administrators.

However, Harmesh Pooni, 42, who claims he is the rightful owner of the Grade II-listed building, has barricaded himself inside. He has blocked the helipads by lashing down upturned tables to stop helicopters landing, while notices in the windows, which were once hatches for the fort's 49 cannon, warn that trespassers will be prosecuted.