THIS week’s nostalgia spotlight looks at the history of the Conwy Tunnel, which celebrated its 30th birthday last week having been declared officially open by the Queen on October 25, 1991.

The A55 road tunnel, built to ease traffic congestion and protect a wild bird haven, cost more than £100 million and took five years and roughly 1,000 workers to construct.

At the time, it was the largest road related construction project in the UK, and it remains the longest road tunnel in Wales.

Carrying the road underneath the River Conwy, the immersed section underneath the estuary is comprised of six steel reinforced concrete tubes, each weighing 30,000 tonnes, that were constructed in what is now Conwy Marina.

A statement from Traffic Wales said: “The underwater sections were floated out to their final positions with incredible accuracy.

“This took a collaborative effort, including a team of 90 divers working 24-hour shifts making approximately 7,000 dives.”

The tunnel was hailed as a 'new link in a golden chain' of road projects, and nowadays boasts a wide and impressive array of hi-tech equipment. 

These include 36 giant fans in each bore, CCTV cameras, emergency telephones, incident detection and public address systems and 1,850 LED lamps.

These lamps adjust automatically to visibility conditions, and are supported by 4km of cabling and 3km of steelwork.