Abbeyton Bridge, on the B966 just north of Fordoun, was shut in July after inspections found serious failings in the 170-year-old structure, which continue to be monitored.

Members of Aberdeenshire Council’s infrastructure services committee (ISC) have now agreed emergency measures to undertake the demolition using specialist contractors.

Should monitoring equipment indicate further deterioration and it becomes necessary to effect an emergency closure of the railway, costs to the council could be around £1-3 million per day to cover disruption to the railway services using the line.

The cost of the demolition alone is expected to be in the region of £1m, over one third of the council’s £2.8m annual budget for bridges and other structures.

This will delay planned works on other bridges and structures around Aberdeenshire, which may deteriorate further in the interim.

At this time no decision has been taken as to whether or not Abbeyton Bridge should be replaced. The primary focus is on carrying out the works necessary to protect the safety of road and rail users.

However, significant investment would be required to replace the bridge and that will have to be considered in the context of current budget provision.

ISC chair, Peter Argyle, said: “The costs associated with an unplanned closure of the line are huge and the only way to remove the risk is to remove the bridge, as it cannot be repaired.

“Under normal circumstances, this work would take two years to plan but this was considered to be unacceptable and early appointment of a contractor experienced in this field, with existing Network Rail approval, has been critical in moving this project forward.

“We appreciate this decision impacts on road users and the nearby Castleton Farm Shop, but it has been taken purely in the interest of safety and to avoid the potential issues caused by an emergency closure of the railway line.”

ISC vice chair, John Cox, said: “Even with all vehicle traffic removed, the bridge remains a danger to the railway and officers continue to monitor any deterioration closely.

“Unfortunately repair is not an option, so we are seeking to demolish it at the earliest opportunity, minimising disruption to the railway, with a view to replacement in the longer term.

“It’s important to realise however that any proposed replacement is likely to run into millions of pounds, and take several years to plan, and there is no financial provision for this within current budgets.”