Ensuring safe passage for 500 years: The need for lighthouse operator Trinity House is undimmed

On a sunny August afternoon, the sea off the southernmost point of the Isle of Wight looks calm enough. The shipwreck map at St Catherine's lighthouse tells a very different story, though; the busy sea lanes to the south are dotted with wrecks.

With seven wrecks, 1753 was a bad year, as was 1836 when the sailing ship Clarendon sank during a howling gale, taking a family of six to their deaths. Disaster struck again in 1970, when the oil tanker Pacific Glory was almost added to the list after an explosion which claimed the lives of 13 souls. Death haunts the waters here.

The human toll from the rocks and reef off St Catherine's would have been far worse had it not been for the lighthouse. And this is a story that can be repeated at all of the 66 lighthouses operating off the coasts of England and Wales, all of which are operated by Trinity House, a body which is as ancient as it is unknown.

Trinity House, a guild or "house" named for the Holy Trinity, was granted a Royal Charter by Henry VIII in 1514. This summer it celebrates 500 years of keeping the British mariner safe at sea. In many ways it was this country's first quango, or arm's-length government body, but it remains true to its roots and is run by a master and a council of 31 elder brethren. These are sailors and safety officials who, five centuries on, remain proud of the vital role they and their predecessors play in "maintaining a way of life we all take for granted".

When you consider that Trinity House survived not only both world wars, but the English Civil War and countless battles with France and Spain, that isn't just institutional bluster or bravado.

"Trinity House is truly a little-known body," said Andrew Booth, a volunteer guide at St Catherine's visitor centre, where the current light dates back to 1838. "Few people know it exists or that is has been responsible for keeping mariners safe for five centuries.

"This site has been automated since 1997 – as have all of Trinity House's lighthouses – so it's now run from the automated control centre in Harwich. Most of our visitors understand we don't have lighthouse keepers any more, but plenty ask why we are still needed in the age of GPS."

As archaic as it seems in a world of radar and satellite navigation, Trinity House insists that maritime lights – the beam from the 400 watt bulb at St Catherine's is visible 26 nautical miles out to sea – remain indispensable.

"The lighthouses we operate are just as vital as they were 50 or 500 years ago," said Captain Roger Barker, navigational requirements director at Trinity House. "Few people realise quite how vulnerable satellite navigation is to solar spots, storms and interference. The mariner – as he did in ancient times – still needs to be able to orientate himself to physical landmarks for navigation." Captain Baker is one of the 31 elder brethren; he admits this sounds quaint, but he insists the outfit is run in a "modern and efficient" way. Few organisations have survived as long as the body responsible for all lighthouses in England, Wales and the Channel Islands. It is all the more remarkable as it doesn't rely on the Treasury for funds, instead taking "light dues levies" from ships in Britain's territorial waters.

Trinity House has faced many challenges since its formation, after boatmen on Deptford Creek petitioned Henry VIII for a body to control navigation on the treacherous river Thames. These have included the battle to wrestle control of Britain's lighthouses from private owners, tales of madness and (alleged) murder on isolated lighthouses, great storms that washed away some offshore lighthouses, and the threat from the Luftwaffe. Even today the 110-year old lens at St Catherine still bears the chips and scars of a 1943 bombing raid that killed three of the 115 lighthouse keepers.

The challenges the body faces today are different, explains Captain Barker. They include sailors taking greater risk and getting "closer to dangerous rocks" because of an overreliance on modern aids. There is the added, growing danger that "reliance on GPS means traditional navigation skills are disappearing".

After 500 years, Trinity House is accustomed to change. It is among the world leaders in developing new electronic navigation systems. At St Catherine's the fog horn has been replaced with cabling from a new differential global positioning system ground station. Installed last year, it's a land-based addition to the GPS system ships use, giving them up to one-metre accuracy to navigate.

Frank Creasey, 71, was the last keeper at St Catherine's and lives in a cottage on the grounds. He said: "Times have changed. Trinity House was a very stuffy and strict organisation back when I worked here and at the Longships lighthouse off Cornwall in the 1980s and 1990s. I used to spend 180 days out at sea a year, but if I visited headquarters in London, I would be forced to use the side entrance because I wasn't a member of the brethren.

"Now things have changed for the better, and the managers wear suits not uniforms when they visit. But I suppose it's good to know that there is 500 years of tradition underpinning what it does."

Captain Barker, while proud of the past, is looking firmly to the future. "As much as 95 per cent of our trade is still carried by sea, and if Felixstowe port were to close tomorrow, the supermarket shelves would start to look empty very quickly.

"Maritime safety and transport are still hugely important to this country, which sometimes people quite don't understand."