The recent announcement of plans to expand Osea Island's resort accommodation to turn around falling profits brought to mind the fascinating history of this mysterious island.

Osea Island was bought in 1903 by Victorian Christian philanthropist Frederick Nicholas Charrington and set up as a temperance retreat for people suffering from drink problems.

Charrington, from the famous brewing family, had witnessed a drunken husband knock his wife down outside a pub (The Rising Sun in Bethnal Green) when she came with her children to beg him for money for food. Intervening, Charrington was also knocked down. Looking up, he saw his family's name on the pub sign.

He immediately abandoned his family's business and set about to use his wealth to combat the negative effects of alcohol. From the 1870s he was active in the East End, but in 1903 he bought Osea Island. He built roads and houses and even imported exotic animals and plants from Australia.

It was set up as a retreat for alcoholics to recover from their addiction. This mission widened to include general relief for unemployed East Enders who were allowed board and lodging in return for manual labour. Up to eighty men lived in wooden huts, working on the construction projects on the island and following strict rules (which of course included total abstention from alcohol).

This was not entirely successful – there are records of inmates escaping to Maldon to raise a ruckus in the local pubs. Boats also smuggled alcohol on to the island.

The Daily Graphic paid a visit to the colony on a bleak, stormy day in 1904. The journalist recorded that the men were given six pence pocket money a week, their wives ten shillings and sixpence (and two shillings for each child) because they had the responsibility for the family.

In 1917 the temperance village (as it had now become) was abandoned when the admiralty requisitioned it for use as a torpedo boat base.

Referred to as "HMS Osea", its inaccessible location made it ideal for the development of a new weapons system – the Coastal Motor Boat (CMB).

The development of small and powerful engines meant that small boats could be propelled at high speed, and the recent development of the torpedo mean that they could carry a weapon that was deadly to large and powerful warships, and use their speed and small size to escape their defences.

The Royal Navy planned to use the boats offensively to travel over minefields and attack German ships in their bases.

HMS Osea had some forty boats, each forty feet long and carrying a torpedo in a trough at the rear. The latter had to be released astern of the boat, which then had to manoeuvre wildly to avoid being sunk by its own torpedo!

Extensive boat sheds, wooden barrack buildings (some of which can now be seen relocated to Heybridge), rails and slipways were built, and a garrison of sailors and Wrens established.

Visits "ashore" across the tidal causeway required a shore pass, and a Captain Dennis recalled that visits to the King's Head were popular, with sailors invariably "just missing" the low tide for their return, and having to stay overnight!

Although these boats were often seen exercising in the Blackwater and further afield, they saw little action in the Great War because by 1918 the German Navy was a spent force.

But in 1919 the boats were given a special secret mission – to enter the Baltic and ferry British agents to and from Bolshevik Russia. In the process, Lieutenant Augustine Wellington Shelton Agar led a mission into Kronstadt Harbour, sinking two Russian battleships and a depot ship. For this he received the Victoria Cross.

These tiny boats evolved into the much larger Motor Torpedo Boats and Motor Gun Boats of World War 2.

Osea Island was under army occupation in World War 2, but its naval function was not repeated, though Maldon boat-builders were to do their share building the new gunboats for the coastal forces.

This was not the end of the island's days as a 'drying out' facility, however. It re-opened as a retreat for wealthy addicts and ran as The Causeway Retreat from 2005-2010. Amy Winehouse was one of its better known inmates.

Osea is now an exclusive and beautiful privately-owned holiday island, with a variety of houses to stay in. It also has a fully equipped recording studio, which has been used by a variety of well-known artists in the past.