Work to refurbish the three land towers on Britannia Bridge, which links Anglesey and the mainland of Wales across the Menai Strait, was set to begin earlier this year.

Designed and built by Robert Stephenson in 1850, the crossing provides a vital rail and road connection between communities on Anglesey with mainland Wales. 

The work will see the installation of support beams underneath the stone lintels at the top of the three towers along the bridge named: Anglesey, Britannia and Caernarfon.   

But the plans came to an abrupt halt after an eagle-eyed birdwatcher spotted a peregrine near the central Britannia tower.

Bird experts were consulted and reported that the behaviour of the male peregrine could indicate a nest. Refurbishments will continue next month on the two other towers, but repairs to the central one have been postponed.

The tower is inaccessible to humans, so the existence of eggs or chicks has not been confirmed, but the behavioural signals were enough to change the refurbishment plans. It is likely that chicks will not leave the nest until August at the earliest.

Peter Caulfield of Network Rail said: “Given the national importance of the birds, we can’t risk disturbing them, so we have postponed the work on the tower until later in the year.”