A £5m (US$6m, €5.4m) programme of improvements by English Heritage at Cornish tourist attraction Tintagel Castle has reached a milestone, with the opening of a footbridge that joins the two halves of the castle for the first time in more than 500 years.

Designed by Ney & Partners engineers and William Matthew Associates Architectural Practice, the bridge spans a 190-foot gorge between the 13th-century gatehouse on the mainland and the courtyard on a jagged headland jutting into the sea. There was once a narrow land bridge connecting the two sites, but this disappeared through erosion during the 15th or 16th centuries.

The bridge is made of of two independent cantilevers. Both stretching out 33m (108ft) the two sides of the bridge meet at the centre of the gorge, with a 4cm gap left to represent the "transition between the mainland and the island, the present and the past, history and legend".

Linked to the legend of King Arthur, the name Tintagel itself derives from the Cornish Din Tagell, which means "the Fortress of the Narrow Entrance" – a reference to the historic crossing point.

The castle is a popular heritage attraction, welcoming more than 250,000 visitors a year. The new footbridge will help to reduce congestion and improve accessibility, making the entire castle explorable for those unable to tackle its steps.

As part of the investment, footpaths around the site have also been improved, helping to reduce the impact on the castle's archaeology and ecology.

Positioned 57m (187ft) above sea level, the bridge is constructed from 47.5 tonnes of steel, 140m of oak, and 40,000 slate tiles that were hand-cut from a quarry just three miles from Tintagel. Members of the public were able to donate funds to help build the bridge and were each allowed to sign one of the Cornish slates that form its walkway. There was also a private donation of £2.5m (US$3m, €2.7m) from Julia and Hans Rausing towards the project – the largest such donation ever received by English Heritage.

"Tintagel Castle has been made whole again," said Kate Mavor, chief executive of English Heritage.

"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.

"As a charity, 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 ‒ protecting the castle's archaeology and bringing its story to life in a brilliant, imaginative way."

The bridge's opening was slightly delayed due to bad weather. It was due to open on 9 August but high winds postponed that until 11 August.