The leader of the House of Commons said officers have been working ‘tirelessly behind the scenes’ to ‘accelerate’ the repairs to the damaged bridge over Farthinghoe Stream.
Northamptonshire County Council confirmed on Friday that work would begin in mid-November and is scheduled to last for three weeks as the Environment Agency has granted consent.
Ms Leadsom said: “Lots of residents and road users have been in touch with me in recent weeks about the closure of the Farthinghoe bridge and the A422, and people have been looking for the road to re-open as soon as possible.
“I’ve been in constant contact with Northamptonshire County Council, Northants Highways and the Environment Agency, and I know they have all been working tirelessly behind the scenes to do everything they can to accelerate the repair works.
“I would like to pay tribute to Cllr Ian Morris, transport portfolio holder at the county council, for his keen attention to the situation.
“The Environment Agency has now given their consent for the works to proceed, subject to certain ecological protections being considered, and I understand that the repairs will take about three weeks to complete.
“It is the aim of Northants Highways to have the road reopened before Christmas, and they will be on site very soon.”
The A422 between Banbury and Brackley has been closed from the recycling centre junction to New Road since August after a routine inspection found it to be unsafe.
A spokesman for Northamptonshire County Council said: “We appreciate that there has been considerable disruption and inconvenience for people and we’re glad that we’re able to give an indication of when the work will be able to take place.
“When we close a road and put a diversion in place we must provide an alternative route on a similar standard of road.
“Diversions are carefully chosen to follow roads of a suitable standard and width to carry all traffic and avoid weight restrictions.”