Dualling the entire 37-mile single carriageway stretches of the A1 in Northumberland could cost up to £1.2 billion, it emerged today.
The figures were revealed at a meeting of the stakeholder feasibility group in Morpeth.
The Highways Agency also revealed at the meeting that full dualling between Morpeth and the Scottish border could be achieved by 2023.
Alternatively, dualling the section of road between Morpeth and Felton could be achieved by 2022 and cost in the region of £160 million to £260 million.
It also emerged that four or five years of preparation would be needed before work could actually start to upgrade the road.
An announcement is expected to be made by the coalition government in the Autumn Statement on December 3 after Chancellor George Osborne revealed to the Berwick Advertiser last month that upgrading the A1 would be a “key priority”.
It will follow the completion of the feasibility study being carried out by the Department for Transport.
A Northumberland County Council report submitted as part of the study estimates that the local economy could benefit by up to £376 million if the road was dualled.
Councillor Ian Swithenbank, policy board member for streetcare and the environment at NCC said: “These figures show what could be achieved with government support over the next few years.
“The council firmly believe dualling will address accident problems, reduce delays and bring clear economic benefits for the county and beyond.”
Liberal Democrat campaigner Julie Pörksen is urging campaigners to keep the pressure up.
Mrs Pörksen said: “The meeting looked in detail at the various parts of the road being considered as part of the Department of Transport’s feasibility studies. It was fascinating to hear how much work has been done thanks to pressure from Liberal Democrat Chief Secretary to the Treasury Danny Alexander MP, who is responsible for infrastructure spending.
“The most heavily used section of the single-carriageway A1 is the Morpeth to Felton stretch and dualling the remaining eight miles here would cost between £160million and £260m. Carrying on the dualling up to Ellingham, a further five miles, is estimated to bring the total up to between £250m to £430m. To dual the entire 37 mile single carriageway stretches would cost between £720 million and £1.2 billion. “The feasibility study is looking at the cost but also the benefits which would come if the work is done, in terms of road safety, reduced journey times, greater reliability along the route and so on, so different stretches of the road will fit different priorities.
“Any work agreed in the Autumn Statement will take a further four to five years to develop before we see diggers on the ground, so this campaign, which has been running for decades, has a long way to go. The devil will be in the detail.”
Berwick MP Sir Alan Beith added: “There is no ‘quick fix’ as far as the A1 is concerned but I am continuing to have regular discussions with Ministers at the Treasury and in the Department of Transport about progress which could be made on the road.”