He looked every inch the old seadog: thick navy-blue jersey, crumpled peaked cap, grizzled beard, and gently smoking pipe. The comfortable belly and the big hand resting easily on the tiller completed the image.

Fumes from the engine intermittently masked the fresh sea air, as his dozen or so passengers surreptitiously looked each other over, the way strangers do when they find themselves in a confined space, even if it is an open boat.

It was a short crossing, merely a few minutes: no time to form more than a general impression. The group was interestingly varied in nationality, in gender, in age (there was a family with young children), and in dress ( from anorak and boots to town shoes and cashmere coat).

With a practised swing of the rudder and a bit of back throttle, the seadog brought the boat in until it bumped gently against the rusty jetty.

The signs were forbidding: 'Authorised Personnel Only', 'Keep Out'. These injunctions were once backed by the full power of the state (and by citizens who had learned obedience to government). Now such notices quietly rust away in the care of a gentler authority.

Up on dry land now, near some buildings, we gather round a man who looks as if he knows what he's talking about. He in turn, as if it's a new experience for him, collects our tickets so that he can tick each one of us off later, on our safe return, or....

'Under no circumstance stray off the marked path,' he instructs us, 'and don't pick up any objects.'

At last we turn to face our distant goal and uncertainly split up into our constituent groups. Some march off briskly straight away; some wait until there's sufficient space separating them from the rest; some, of course, dither in the middle.

The path we are taking, whose end is out of sight, leads to...well, in the end, probably Denmark. On one side a 700-year-old earth bank, put up to divide rich grazing land from salt marsh, blocks the view and gives a claustrophobic feel to the open space. On the other side - past the grazing land, past the shingle on the distant horizon, beneath the vastness of the East Anglian sky, at the edge of the eye's resolution - stand strange and sinister shapes. We set out towards them.

All this started back in 1913. You can read all about it on the wall in the information building: the number of desks, the number of chairs, the distribution of this and of that, all carefully planned and organised. The actual opening was in 1915, at the height of World War 1. By 1918 there were 600 souls working in this out-of-the-way spot on the Suffolk coast. The photographs tell us what they were up to, or at least the helpful captions do.

Old photos always look a bit odd, but the contraptions portrayed in these are odder than most. What structures and mechanism would you imagine necessary to produce and test a bomb sight or to test machine guns for greater accuracy (to kill more people, that is to say - though the captions don't)? What do you need to improve aerial combat efficiency?

Such was the creative hum here that someone had the idea of providing parachutes for pilots baling out. A good idea, you might think; but clearly considered aberrant in an environment dedicated to destruction. The plans to test such a humane device were dropped: the top brass were worried that it might weaken the fighting spirit of the airmen. You can read all about that on the information wall too.

When the 'war to end all wars' was over and the world breathed a sigh of relief, there was barely a pause in activity: the Royal Flying Corps moved out and the Armaments Experimental Establishment moved in - to start testing more weapons.

By 1939 the RAF moved in, with an army of civilian scientists. Throughout the Second World War they fired more guns and dropped more bombs; and, from the dark space high up on the bomb-ballistics building, protected with steel plates, they filmed the bombs' flight, using high speed cameras with more dedication than any pornographer.

When peace broke out in 1945, the reign of this open-air warfare laboratory still had some years to run. By 1956 the first six atomic weapons test cells were completed; and on August Bank Holiday that year the test of Britain's first atomic bomb, 'Blue Danube', was carried out.

Back in 1937, it had been noticed that aircraft could reflect radio waves. Some 30 years later 'Cobra Mist', an over-the-horizon radar jointly built by the UK and US, began operation amid these salt marshes. Directed at eastern Europe, its purpose was to detect missile and satellite launches. This purpose was never fulfilled - at enormous cost. The buildings remain, though not the giant horseshoe antenna, and today house the BBC World Service transmitters, broadcasting to the area which had once been spied on.

Our present-day host, the National Trust, provides a useful guide book . It comes with a coloured map and a list of points of interest on the 'red trail': Old Grazing Marsh; Site of First World War 100-ft Span Hangar; Vegetated Shingle; Lethality and Vulnerability Trials. And: 'AWRE Site'.

'Warning: this is a prohibited place within the meaning of the Official Secrets Act'. That large notice, faded and rusty like the rest, now hangs on the wall of the information building instead of on the perimeter of the site. Its message, now merely an exhibit, causes uneasy amusement to those who have paid to see what it once guarded. But we ignore its warning at our peril.

When they were testing bomb sights here, they often missed the target. Once they bombed nearby Aldeburgh, for many years the home of Benjamin Britten, a PPU member till his death. In his 'War Requiem' Britten referred to the poet Wilfred Owen's words: 'All a poet can do today is warn'. The Requiem was intended as such a warning. But, then as now, warnings seem to be powerless; and sometimes they inadvertently help to deceive rather than inform. Threats can do the same: the Official Secrets Act did little to prevent the 'enemy' from knowing what was going on this abused piece of land, but it kept hidden from the rest of us what the state was doing 'on our behalf'.
The guidebook has a supplement; it tells us that 'the BLUE extension to the RED TRAIL is now open', and on the newly-made path a large blue arrow points us to 'Lab 1'. Here, inside the thick concrete walls, and buried under tons of shingle in case the experiment got out of hand, they put Britain's atom bombs through their non-nuclear paces. The entrance leads into a dark corridor and along it, past lightless rooms echoing with the sound of dripping water, to the now roofless, rusting laboratory. Here people - who at the end of the day went home to their families and played with their children - worked to ensure that hundreds of thousands of people could be annihilated in an instant.

In an item about the beach, and without irony, the guide book makes its only social comment: 'Debris and rubbish from ships, ferries and coastal towns litter the tide-line, a sad indictment of our irresponsible behaviour'.

Lab 1                                    

'Saving Private Ryan' may, as its enthusiasts claim, portray battle 'authentically'. But it is here at Orford Ness, and in other such places, where the war goes on. The fuller meaning of war is to be found, not in the heat of battle where 'life or death' is clear-cut, but on this and the many other similarly violated stretches of land where, with a mixture of indifference, enthusiasm and a great deal of scientific and technical ingenuity, our future is shaped; and for many foreclosed.

If evil exists, this is its comfortable home.