The M3 shuts both ways between junctions 9 and 8 from 9pm on 23 October and 6 November to demolish old bridges. The second covers Winchester's bonfire night.

The M3 will close in both directions between junction 9 at Winchester and junction 8 for two full weekends this autumn. National Highways is demolishing the old bridges that sit directly above the motorway at junction 9.

The dates are:

  • 9pm Friday 23 October to 6am Monday 26 October, to take down the northern bridge section
  • 9pm Friday 6 November to 6am Monday 9 November, to take down the southern bridge structure

National Highways published the dates in an update on its M3 junction 9 scheme page dated 25 September. It says the motorway has to shut because the old structures are directly over the carriageway. Closing it gives the demolition teams and drivers a safe working area.

The second weekend takes in Saturday 7 November, the night of Winchester’s bonfire and fireworks at North Walls Recreation Ground.

Two shorter closures come first, from Friday 9 October

Before the motorway shuts, there are two shorter closures on the weekend of 9 October. Both are on the same National Highways update.

Closure When Why
M3 northbound exit slip road at junction 9 9pm Friday 9 October to 6am Monday 12 October Widening the slip road
M3 northbound, junction 10 to junction 8 Overnight, 9pm to 6am, on Friday 9 and Sunday 11 October Putting barriers in and taking them out
M3 both directions, junction 9 to junction 8 9pm Friday 23 October to 6am Monday 26 October Demolishing the northern bridge section
M3 both directions, junction 9 to junction 8 9pm Friday 6 November to 6am Monday 9 November Demolishing the southern bridge structure

The northbound exit slip is the one drivers coming from Southampton use to leave the motorway at Winnall. For that weekend they follow a signed diversion. The two overnight closures between junctions 10 and 8 take the whole northbound motorway out past the city, not just the junction.

National Highways says the bridge demolition will carry on day and night to keep the disruption as short as it can. Signed diversions run for every closure. The agency has published each route as a map on its scheme page rather than as a list of roads.

What is already shut at junction 9

These closures sit on top of two restrictions that are already in place:

  • The M3 northbound entry slip road at junction 9 has been closed since 31 July and stays closed until winter 2027. There is no way onto the M3 towards Basingstoke from the Winnall roundabout.
  • Easton Lane westbound, towards Tesco, is down to one lane until late November, so that work can start on the embankment and the old south-west subway.

Both come from National Highways’ own updates on the same page. Our Winchester roadworks page carries the full list of closures in the city and district, including the county council’s orders.

What it means for you

  • Driving to London, Basingstoke or the A303 on either weekend? The motorway north of Winchester is shut from Friday night to Monday morning. Follow the signed diversion and allow extra time.
  • Coming to Winchester from the north? The same applies in reverse: the M3 southbound is shut between junction 8 and junction 9.
  • The October weekend is the start of half term. Hampshire schools are off from Monday 26 to Friday 30 October (Hampshire County Council), so the motorway reopens at 6am on the first day of the holiday. Our term dates page has the full year.
  • Going to the bonfire on 7 November from outside the city? If you would normally come down the M3 from Basingstoke, plan a different route or come by train. The procession starts at 6pm and the fireworks at about 7.45pm, according to the organiser, Winchester Round Table.

National Highways says closures “can change at short notice”, especially when weather stops work. Check its daily closures report on the day. The scheme team is on 0300 123 5000 or at M3Junction9Improvements@nationalhighways.co.uk.

Why the junction is being rebuilt

The scheme turns junction 9 from a roundabout into a free-flowing interchange, so traffic moving between the M3 and the A34 no longer has to stop at the roundabout. National Highways puts the cost at £268 million to £322 million, to be finished within the 2025 to 2030 road period.

When the plans were consulted on, the government said about 110,000 vehicles used the junction every day, including more than 5,500 lorries (GOV.UK). National Highways calls removing the old bridges “a major milestone” for the project.

Sources