M3 J6 Black Dam Improvements

Scheme outline

Junction improvement for the roundabout where the M3 meets the A30 and A339 in Basingstoke. A new road will carry northbound traffic through the centre of the roundabout and the southbound route will be widened for 4 lanes. All approaches will be widened and improved.

This scheme was completed in and we're no longer accepting updates or changes to this page.

October 2014 to February 2016
Junction improvement
for use by all traffic
Highway authority


13 October 2014

Work started last night, the 12th October at 10pm. The southbound approach to the roundabout has been reduced to two lanes which had an immediate impact on congestion. Other approaches including the westbound A30 have also been reduced in width.

4 June 2015

Completion was originally due to be summer 2015, owing to delays re-routing utilities (including the workers breaching a gas main!) this has now been pushed back until October. Certainly progress appears slow, the new stretch of road through the roundabout has only just been built and some significant closures are planned to start some of the other major works. Lane widening at the approaches and on the spur towards the M3 seem advanced. Traffic congestion is horrendous at peak times putting huge pressures on the village of Old Basing which is the only real diversion route. They have tried dissuading drivers through placing signs on roads leading to the village claiming no access other than for Old Basing and Lychpit. Access is not however actually blocked.

1 October 2015

Gantries have been erected on 3 of the 4 approaches. With little attention, the project has slipped further to a November 2015 completion date, which will mean a 13 month construction period instead of the original 6 months or so. One thing to note is that, despite in the increase in capacity planned, the newly expanded 3 lane southbound spur to the M3 actually merges back into 2 lanes before reaching the junction. Seems to defeat the objective really!

13 November 2015

The Highways England website (at time of writing) still has a completion date of November 2015. In fact, HE have informed Basingstoke & Deane Borough Council that work could continue until February/March 2016. They claim this is due to "unforeseen problems with diverting and protecting utilities". Work is now nearing three times the original estimated duration! The impact on travel in the area is severe.

4 February 2016

Highways England indicate that 08/02/16 will be the final night closure, which will result in full scheme opening on 09/02/16, albeit many months late!

8 February 2016

Black Dam re-opened fully this morning. There will still be some minor works to be done concerning landscaping etc.

More information


With thanks to Toby's and Jonathan Harmer for information on this page.