The thing that makes Barafundle Bay singular is an absence: there is no road to it. Almost every famous British beach has, somewhere behind it, a car park, a promenade, a chip shop, a sea wall, a row of houses. Barafundle has none of these touching the sand. The nearest you can drive is the National Trust car park at Stackpole Quay, and from there the only way to the beach is your own two feet — about half a mile (0.8 km) along the Pembrokeshire Coast Path, up and over a flight of stone steps set into an old wall, and down through dunes and a band of pine. There is no vehicle access, no kiosk, no toilet, no bin, and no lifeguard on the beach itself. Everything you want on the sand, you carry in; everything you leave with, you carry out.

Why the wall and steps are there at all is the heart of the story. They are not a council footpath. Barafundle was a private beach belonging to the Cawdor family — the Campbells, Earls Cawdor — who owned the Stackpole Estate. The wall on the northern approach enclosed their land, and the steps were cut to ease the family's own access down to a beach that, for most of its history, ordinary people had no right to use. So the very barrier you climb to reach Barafundle is a relic of the time it was kept from the public. The estate around it was a designed aristocratic landscape: the Campbells built the Palladian mansion Stackpole Court in the 1730s; Sir John Campbell, inheriting in 1777, dammed a limestone valley to create the Bosherston lily ponds and planted thousands of trees; the eight-arch bridge linking the court to the deer park and the quay was built in 1797; and Stackpole Quay itself — one of Pembrokeshire's smallest harbours — was built by Earl Cawdor at the end of the 18th century to ship out limestone from his quarry and bring in goods for the house.

Then the family left, and the absence of development became permanent. In 1938 the Ministry of Defence requisitioned around 6,000 acres of the estate for the Castlemartin tank range. Soldiers billeted in Stackpole Court stripped lead from the roof; dry and wet rot followed, and the mansion was demolished in 1963. The Campbells retreated to their Scottish estates, and in 1976 the coast, woodlands, lakes and beaches passed to the National Trust. Because the estate was never sold off for housing or holiday camps, Barafundle skipped the entire 20th-century apparatus of the seaside resort. There was no developer to put a road in, and once the National Trust held it, there never would be. The beach is undeveloped not by accident of remoteness alone but because of a specific chain of ownership: private deer park, then military requisition, then conservation trust — three regimes in a row, none of which had any interest in building a car park on the sand.

The geography makes the walk worth it and the swim dangerous in the same breath. Barafundle faces east, tucked between limestone headlands, so it is sheltered from the prevailing south-westerly winds that batter the rest of this coast. On a calm day that shelter gives you flat, clear water and fine golden sand backed by dunes — the look that earns the bay its Caribbean comparisons and a 2004 listing among the best beaches in Britain. But the same sand that shelves so pleasantly for paddling shelves quickly into deeper water, and the official guidance for the bay is explicit that strong rip currents are likely and that swimmers must check the tide to avoid being cut off against the cliffs. There is no lifeguard to pull you out and no road to speed an ambulance in. The remoteness that filters the crowd also filters the help.

The land around the beach is a working nature reserve, not a backdrop. Barafundle sits within the Stackpole National Nature Reserve, managed by the National Trust in partnership with Natural Resources Wales and protected as a Site of Special Scientific Interest. Choughs — the rare red-billed, red-legged crow — nest on the cliffs; razorbills and guillemots crowd the ledges at Stackpole Head; grey seals use the coves; otters live in the inland lily ponds the Campbells dammed; and the estate holds the largest colony of greater horseshoe bats in Wales, roosting in the old estate buildings and trees. The geology itself is designated: the cliffs here are Carboniferous limestone, around 330 to 347 million years old, and the folds and fault-collapse breccias exposed at Stackpole Quay are notable enough that the structure featured on the cover of the first issue of the Journal of Structural Geology in 1979. You are walking through a designed landscape, a protected ecosystem, and a textbook geological section to reach a beach with nothing built on it.

That is the whole argument for Barafundle: it is one of the most admired beaches in Britain precisely because it was never made convenient. The wall you climb was built to keep you out; the lack of a road is the reason the sand is still empty enough to deserve the praise. The reward is a sheltered east-facing bay; the price is a half-mile walk, a flight of steps, no facilities, no lifeguard, and a current that does not care how far you came.