£1.25 million renovation work on Iron Bridge to be delayed until the spring

It had been anticipated sprucing up the Iron Bridge would start this month after English Heritage announced the revamp early last year.

But the charity said April now looked the earliest starting point for work to begin.

The programme will involve work on radials and braces holding the bridge together, deck plates and wedges, the main arch and the stone abutments on either side of the river. It is the single largest conservation work ever undertaken by English Heritage.

Tom Jones, spokesman for the charity, said: "The work at the Iron Bridge will now probably begin in the spring, rather than January. Following discussions with stakeholders, it was decided that erecting scaffolding after the Easter holidays was preferable.

"The detailed programme is still to be confirmed but we do hope to be on site in late April, early May.

"We are very excited about the project, which is our charity's largest conservation project to date." The landmark remains Britain's best-known industrial monument and the world's first iron bridge.

But it is suffering from cracking due to stresses in the ironwork dating from the original construction, ground movement over the centuries and an earthquake at the end of the 19th century.

The cast iron pieces will be carefully cleaned and conserved, reinstalled or replaced where "absolutely necessary". The bridge will also be repainted as part of the project.

Erected in 1779 over the River Severn in Ironbridge, the historic bridge was the first single span arch bridge in the world to be made of cast iron. It marked a turning point in British engineering as cast iron became widely used in the construction of bridges and buildings.

Works to strengthen the bridge have been carried out over the years as the sides of the Gorge move inwards.

Conservation of the bridge follows three years of surveys and investigations that conclude this week with engineering experts surveying the structure, which sometimes involves abseiling from the bridge.

The bridge gave its name to the spectacular wooded gorge that was once an industrial powerhouse.

The Ironbridge Gorge is now a World Heritage Site.

Kate Mavor, English Heritage's chief executive, said: "Iron Bridge is one of the wonders of the modern world. An iconic symbol of the Industrial Revolution, it is arguably the most important bridge ever built and without doubt, one of the most important sites in our care.

"This conservation project will ensure that both its revolutionary structure and the story those cast iron arches and beams tell, will continue to inspire us for generations to come."