Britannia Bridge (1970) Menai Strait, Anglesey, Wales

The Britannia Bridge, known locally as the Tubular Bridge, was the scene of a disastrous fire, on the evening of May 23rd 1970. A ground breaking design by Robert Stephenson, the bridge had been commissioned and built to ease the plight of Irish Members of Parliament, who since the Act of Union of 1800 had regularly to undertake the journey between London and Ireland. With the advent of rail travel, the provision of a bridge across the Menai Strait, linking the island of Anglesey - from where the ferry sailed to Ireland - and the mainland would ease the long and arduous journey.

The bridge was opened by its designer in 1850, with Stephenson himself driving in the last of the 2 million rivets used in its construction. The two main spans measured over 140 metres in length, two other spans were each just 70 metres and Stephenson estimated that 13,500 tons (12,247 metric tonnes) of iron was used. Each railway line, the ‘up’ and ‘down’ to London, travelled through its own rectangular wrought iron ‘tube’ with a masonry tower each at the entrances, two towers in mid section and a central tower. The bridge traversed the strait at a height of just 46 metres above low water level. A single roof, added some years after construction, ran the length of the twin tubes and was covered in a heavy material and coated with tar. A maintenance pathway on the roof facilitated the application of fresh tar as it was required.

On that fateful, spring evening some boys, searching out bats and birds’ nests, lit a piece of paper and held it up to one of the tubes, just where it met the stone entrance. The tarred, timber joint between the two caught fire and buffeted by the wind, the chimney like effect of the tubes, air currents at the exposed site and other forces, the fire soon became an inferno which could be seen over 20 miles away. Firefighters worked through the night, but in vain. The tubes were seriously damaged, visibly sagged and the two main spans were in imminent danger of collapse.

No deaths or serious injuries occurred and the fire was classified as accidental, meaning the boys were not prosecuted. Getting the rail link going again was a priority. Initially the tubes were supported by newly constructed arches, allowing rail traffic to resume in one tube under 2 years after the accident, following which a new deck took shape on the site of the obsolete tube, across which trains then travelled. The second tube was then taken down. The masonry towers of the old bridge remain. Finally, in 1980, a road deck, the A55, was added, making the new Britannia a double decker bridge.