M3 junction 9 improvements project update - 13/10

During mid-September the contractors successfully switched traffic into a contraflow system on the M3 southbound. They’ve now begun work to construct the new A34 underpass.

Through October 2025, they will continue to remove vegetation from various locations. Before any clearance begins, they carry out thorough ecological checks to identify wildlife and nesting birds.

Once work is complete, they will replant and deliver several environmental enhancements — including restoring chalk grassland habitats. Find out more about the Chalk Grassland restoration: Chalk Grassland factsheet.

• Overnight on Tuesday 14, Wednesday 15 and Thursday 16 October they are closing the M3 southbound between junctions 8 and 9 (9pm to 6am) - Vegetation clearance and Vehicle Restraint System removal
  • Diversion: M3 northbound junctions 8 and 9 diversion
• On Friday 17 and Saturday 18 October they are closing the A34 at Three Maids Hill and A33 the Cart and Horse junction southbound (9pm to 6am) - A34 access construction
  • Diversion: A34/A33 southbound diversions
• Overnight on Monday 20, Tuesday 21, Wednesday 22, and Thursday 23 October they are closing the M3 junction 9 northbound exit slip road (9pm to 6am) - Vegetation clearance
  • Diversion: M3 northbound exit slip road diversion
• Overnight on Sunday 26 October they are closing the M3 junction 9 southbound entry slip road (9pm to 6am) - Vegetation clearance
  • Diversion: M3 southbound entry slip road diversion
• Overnight on Monday 27, Tuesday 28, Wednesday 29, Thursday 30 and Friday 31 October they are closing the M3 northbound between junctions 9 and 8 (9pm to 6am) - Vegetation clearance
  • Diversion: M3 northbound junctions 9 and 8 diversion

Our diversion routes are designed to suit all vehicle types.

We advise you not to use a Satnav when following any of our diversions because there is a risk it could direct you down an unsuitable road or back onto our network when it is closed.