Closures will be in place between Junction 3 and Junction 5 from Friday September 28 to Monday October 1.
And for drivers travelling westbound, there could be a 60-mile diversion to get between the two junctions, which will take them north along the M3 and A34, before taking the A303, A338 and A36 to get back to the motorway.
Why is the M27 being closed?
The motorway will be shut this weekend for roadworks on the Romsey Road Bridge.
The 40-year-old bridge is nearing the end of its life and is in need of replacement.
The only safe way to do this is to close the motorway while this takes place.
The Romsey Road Bridge is well used and carries tens of thousands of vehicles daily.
The bridge is actually made up of two individual bridges, both will be closed for three full weekends while the existing bridge is demolished and a new one installed.
The replacement bridge has a different design and will have a lifespan of 120 years.
Will there have to be future closures?
Unfortunately, yes. The weekend closures will take place as follows:
– 10pm on Friday, September 28, to 5am Monday, October 1
– demolition of existing west bridge
- 10pm on Friday, April 26, 2019 to 5am Monday, April 29, 2019 – installation of new bridge
- 10pm on Friday, October 13, 2019, to 5am Monday, October 21, 2019 - demolition of existing east bridge.
During the work, the M27 will be closed in both directions between junctions 3 and 5, and the A3057 Romsey Road over the bridge will also be closed.
When the A3057 reopens on Monday morning, there will be a single lane over the bridge, which will be traffic light controlled.
Here are the full routes of the diversions in both directions:
M27 will be closed in both directions between Junction 3 and 5 this week
Traffic on the eastbound M27 will be diverted off the motorway and directed towards Romsey.
High-sided vehicles will be diverted along the A27 through North Baddersley to re-join the M27 at junction 5, avoiding the low bridges in Romsey.
Vehicles not exceeding the height limit will be diverted along the A3090 to the M3 just south of Winchester.
The westbound M27 will be diverted via the M3, A34, A303, A345, A36 to re-join at junction 2.
The westbound diversion will also be signed from junction 8 on the M3 so that southbound M3 traffic can join the diversion route by using the A303.
There will also be a diversion route for the A3057 (Romsey Road) itself.
This work has been carefully planned and agreed with Hampshire County Council, Southampton City Council, Hampshire Police and other stakeholders.
While the motorway is shut, Highways England and its contractors will use the closure to carry out routine maintenance, such as vegetation clearance and drainage work.