A340 Thornycroft Roundabout improvements

Scheme outline

As part of a range of improvements to junctions around Basingstoke, Hampshire County Council propose to improve the A340-A3010-B3400 Thornycroft Roundabout to relieve the congestion it frequently suffers.

Similar to the plans for other nearby junctions, widening is proposed for all approaches to provide additional lanes, more lanes will be provided on the gyratory itself, and entry points will be controlled by traffic lights. There will also be improvements for pedestrian crossings.

The present roundabout was built as part of the works for Basingstoke New Town and was originally intended to be temporary, with land set aside for this major junction of two dual carriageways to be converted into a compact cloverleaf junction. Most of the land for this is still available but these works will prolong the life of the roundabout rather than remodel the junction.

Advance works start in 2017, while the main works will run from 2018 to 2019.

Under construction
Junction improvement
for use by all traffic
Highway authority
Enterprise M3 LEP/local contributions


18 June 2019

Signs are now up saying works are starting on the 26th of June, with the works lasting 66 weeks.

7 July 2019

50mph speed limits are now in place on the approaches to the roundabout, dropping to 30mph for the roundabout itself. Cones have been set up to block off the left lane where each approach meets the roundabout.

More information


With thanks to Jonathan Harmer for information on this page.