This is why repairs to world's last surviving iron bridge have taken so long in Milton Keynes town

A bridge closure that has caused havoc for a town is due to end shortly, MK Council has announced.

Tickford Bridge in Newport Pagnell, known by locals as the Iron Bridge, is a Grade I listed Scheduled Monument and is one of the last iron bridges in Britain that still carries main road traffic.

Built in 1810, It is believed to be the oldest cast iron bridge in the world that is still in constant use.

This status means any works on the famous structure, even minor repairs, must be done with full approval and permission of the relevant authorities, including Historic England.

Work started on Tickford Bridge in July to carry out “essential repairs and maintenance works” and a 16 week closure notice was imposed. The closure essentially splits the town in two and can mean a detour of several minutes for some drivers.

The first snag came in August, when the Historic England inspector visited the bridge and raised concerns over the painting works.

"This resulted in a change to hand preparation only to retain the historic layers of paint as much as possible,” said a spokesman for MK City Council.

"We were also required to provide detailed documents on our plans and processes for this stage of the works. This additional work and various other tests delayed the painting stage as we were unable to begin without the official approval from Historic England.”

When work finally began, there was another obstacle – in the form of a pigeon’s nest, which was discovered while the scaffolding was being erected on the underside of the bridge.

"As all active bird nests are protected under the Wildlife & Countryside Act 1981, we had to consult an ecologist who visited the site in early September and found two active nests, one with eggs and one with recently hatched chicks,” said the council spokesman.

“For this reason, a temporary halt to the works had to be called so that a specially designed protective barrier could be installed around the nests. Once the ecologist had confirmed the birds had left the nests in early October, works could restart.”

Work re-started, but soon came the next snag. Once the defective paint layers were removed from the bridge, “serious structural defects” became visible - including cracks in the cast iron itself.

This meant additional plans for repair work had to be devised and set to Historic England for approval/

In the meantime, due to the high levels of lead-based paint that were used on the bridge in the past, the structure had be shrouded in protective screens to retain contaminants and prevent pollution.

The permit for the bridge closure expired on November 14 but this has now been extended until November 25.

The aim to to get the bridge finished and open for one of the town’s biggest events – the Christmas Lights switch-on scheduled for November 26.

"We are confident that this date can be met ... We understand the importance of this event for the local community,” said the council spokesman.

Meanwhile nearby Tyringham Bridge, also a scheduled monument, is due to re-open on Friday following intensive repairs to damage cuased by a road traffic incident in August.