Legend has it that when Uther Pendragon, the King of the Britons, fell in love with the wife of the Duke of Cornwall, Igraine, he convinced Merlin to transform him into the likeness of her husband and stole across a narrow neck of land to spend the night on the island fortress of Tintagel, conceiving King Arthur in his passion.

Now, for the first time in 500 years, visitors to the ancient Cornish castle will be able to follow in Uther’s footsteps thanks to a new £5 million bridge that will open on Sunday after a brief delay occasioned by a severe weather warning. That’s assuming the visitors don’t suffer from vertigo: the steel and slate span consists of two cantilevers of 33 metres (108ft) each, which don’t quite touch in the middle.

This leaves a 40mm gap with a view down 60m into the gorge where the land bridge once stood — it is believed to have collapsed some time in the 15th century. According to the architects, William Matthews Associates, the gap represents “the transition between the present and the past, history and legend”, although it seemed less poetic last week when a slight wobble was tested by a large group of workmen jumping up and down.

And while there is no concrete proof that King Arthur and his round table – or the later story of Tristram and Isolde, which is also set at Tintagel – had any basis in fact, recent discoveries of amphorae fragments prove beyond doubt that between the 5th and 7th centuries, Tintagel was a major seat of power, with large amounts of wine and olive oil being brought from as far afield as Greece and the Levant and probably traded for Cornish tin.

“There’s evidence of a vast quantity of exotic imported goods,” Dr Jeremy Ashbee, chief curator of English Heritage, said, “not least from the amphorae, which were the Tetra Pak of the day. It shows there was someone of real importance in Cornwall.”

Whatever became of its Dark Age-inhabitants, Tintagel was subsequently given a new lease of life in the 13th century when a later Earl of Cornwall - Richard, the fabulously rich younger brother of Henry III - built a castle on the site, called “Din Tagell” in Cornish, meaning “the Fortress of the Narrow Entrance”.

With the remains of a substantial gatehouse on the mainland, and a banqueting hall on the island, it is almost certain to have stretched right across the land-bridge, a strip of rock and earth so thin that, according to the medieval cleric, Geoffrey of Monmouth, “three armed men would be able to defend [it], even if you had the whole kingdom of Britain at your side”. The span is therefore supposed to recreate the missing part of the palace as well as save visitors the trudge up a steep set of steps to the top.

“Tintagel Castle has been made whole again,” Kate Mavor, English Heritage’s Chief Executive, said. “Once more, people will cross from one side of the castle to the other and their footsteps will echo those from hundreds of years ago. English Heritage’s core purpose is to care for historic sites like Tintagel Castle and to inspire people to visit them. Our new Tintagel bridge does both.”

Yet the bridge, which will be used by an estimated 250,000 tourists a year, is not universally popular. Local residents have complained of “Disneyfication” after Merlin’s visage was carved into the cliff-face and a sculpture of a knight was helicoptered onto the top, while the extended closure of the site has also hit local businesses.

“The bridge [and] Merlin all contribute to Tintagel being ‘driven’ as a cash cow by English Heritage, like Stonehenge,” Bert Biscoe, a local independent councillor, said. “The charge of ‘Disneyfication’ still applies and the increased footfall, the commercialisation of one of the most important archaeological sites in Britain, and a central element in the Cornish and Celtic story, betrays an approach to managing our heritage which affects those very factors which are most important: authenticity, discretion and respect.

“The bridge is a pretty thing, but it has been imposed on a protected landscape, and into protected geology, without due respect for either. Such a development should be by mutual consent.”

∗ ∗ ∗