The Duke of Northumberland has backed growing calls for the A1 to be upgraded by signing a petition on Tony Blair's website.
The duke is among more than 2,000 people to have now added their names to the online protest on the Downing Street website, which is calling for the key route to be dualled between Berwick and Morpeth.
Northumberland MPs Alan Beith (Berwick) and Peter Atkinson (Hexham) have also backed the protest which has gained hundreds of new supporters since The Journal revealed details of the petition last week.
The growing calls for action come as Conservative leader David Cameron this week recognised the importance of the A1 to the region's economy and as his party signalled upgrading the route could be a key priority for it.
Last night, Mr Atkinson welcomed the duke's support for the petition and urged the North-East to get behind it.
"The people of the North-East feel they are being short-changed over the whole question of road funding. We have the fastest growing car ownership in the country, but a paltry settlement to cover all transport infrastructure - road, rail and bus.
"This is having an impact on the economic development, particularly in Northumberland," added the Conservative MP.
Mike Parker, from the North-East chamber of commerce, said: "We are 100% behind the petition and we would urge anyone in the region to sign up to it.
"The dualling of the A1 is long overdue and it is high time the Government realised the pressing need to make this infrastructure improvement."
Berwick Tory Parliamentary candidate Anne-Marie Trevelyan said upgrading the A1 was one of the single most important issues to local people in terms of safety and helping the economy.
Referring to the online petition, she added: "It shows just how critical this issue is to giving north Northumberland the economic and regeneration boost that it needs to move forward into the 21st Century."
Mrs Trevelyan also praised campaigner Kenny Patterson for coming up with the idea of launching the petition on the Prime Minister's website.
"This is an excellent idea and it shows initiative and we are very keen to make our voices heard," she said.