Chancellor George Osborne has said there is a “compelling case” for upgrading the A1.
It comes as a feasibility study is commissioned by the Department for Transport to dual the road key to businesses in Northumberland.
The Chancellor said: “Anne-Marie has personally raised with me the need to support rural businesses and communities and she has put firmly on the table the issue of the A1 and what we can do to make it a better road.
“On the back of Anne-Marie’s campaign we have commissioned the feasibility study and we must wait to see what it finds, though personally I believe there is a compelling case.
“The very fact that there is a study underway is a huge advance on where we were before and that is down to the tireless campaigning and energy that Anne-Marie and her supporters have put into this cause.”
Mr Osbourne was in Berwick last week to announce Rural Growth Network cash.
During the visit he met with Ms Trevelyan to discuss the long-standing calls from residents to dual the road along its entire stretch through the county.
Ms Trevelyan added: “Residents and businesses know very well that dualling the A1 through Northumberland is vital, not only to the local economy but also in terms of safety.
“The benefits that a fully dualled A1 could bring would be felt both north and south of the border so it must remain a key strategic aim.
“That’s why I was delighted that the Chancellor accepted my invitation to come and see for himself the potential that is waiting to be unleashed.
“Keeping the issue high on the Government’s agenda is my number one priority and this visit shows that we are making progress, but we must continue to make the case for a better deal and a fully dualled A1. I encourage anyone who wants to see the A1 dualled to support the campaign at www.dualthea1.com .”