A major £27 million programme of roadworks on the M6 Thelwall Viaduct is set to begin on Tuesday, 1 September, with drivers being warned to prepare for more than a year of traffic restrictions on one of the North West’s busiest motorway links.
National Highways is replacing the bridge joints on the Thelwall Viaduct in Warrington, which carries the M6 across the Manchester Ship Canal and River Mersey between junctions 20 and 21.
The scheme officially begins on 1 September, although the first work will take place underneath the viaduct at Warrington Road rather than immediately causing major restrictions on the motorway itself.
More significant disruption will begin later in September as National Highways starts installing the traffic-management system required for the project.
From 12 October, a 24-hour contraflow will operate on the M6 between junctions 20 and 21, with a temporary 40mph speed limit applying on both carriageways.
During the daytime, National Highways plans to maintain four lanes of traffic in each direction, with part of the southbound carriageway used to carry one of the northbound lanes.
Between 10pm and 5am, four lanes will remain available southbound while northbound traffic will be reduced to one lane during the first phase of the work.
The northbound exit slip road at junction 21 is expected to remain open throughout.
Before the main contraflow begins, drivers face a series of overnight lane restrictions and complete motorway closures while the new layout is installed.
Lane closures begin on 21 September, followed by further restrictions throughout the remainder of September and early October.
The M6 northbound between junctions 20 and 21 is scheduled to close completely overnight on 28 and 29 September.
Full southbound overnight closures are then planned for 30 September and 1 October.
Another complete northbound overnight closure is scheduled for 11 October immediately before the permanent contraflow comes into operation.
During full closures, National Highways says the signed diversion will use the M56, M60 and M62, meaning drivers should expect significantly longer journeys.
The restrictions are particularly important for passengers and professional drivers travelling between Liverpool, Warrington and Manchester Airport, where delays on the M6 can quickly affect journey times across the wider North West motorway network.
Passengers wanting a pre-booked alternative for journeys between Liverpool, Manchester and the region’s airports can use Manpool Transfers for private airport and long-distance transfers.
National Highways says the viaduct’s bridge joints have reached the end of their operational lifespan and replacing them is necessary to maintain the safety and reliability of the structure.
The work will be completed in several stages rather than closing the viaduct for an extended period.
From mid-October until March 2027, work will concentrate on replacing joints on the northbound side.
A southbound contraflow is then expected to be introduced during spring 2027, allowing work to move onto the southbound side of the viaduct.
Bridge-joint replacement and removal of the contraflow are currently scheduled to continue until December 2027.
A final phase involving resurfacing, new road markings, road studs and replacement traffic sensors is planned for winter 2027-28.
National Highways says the contraflow has been designed to keep the same number of lanes available during the daytime while reducing the need for prolonged full motorway closures.
However, the 40mph restriction and altered lane layout mean motorists using the M6 through Warrington should allow additional journey time once the main traffic management comes into effect.
Taxi, private hire and airport-transfer drivers using the route should be particularly aware of the overnight restrictions, as several of the closures fall during periods when drivers may be travelling to Manchester Airport for early-morning flights.
National Highways says the programme may change because of weather or unforeseen circumstances, so motorists are advised to check live traffic information before travelling.
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Sources
National Highways – M6 Thelwall Viaduct Bridge Joint Replacement Scheme
The Warrington Wire – M6 Thelwall Viaduct 40mph Contraflow From 12 October
