M25 Widening J16-23

Scheme outline

Online upgrade of the existing chronically congested 3-lane motorway to dual 4-lane standard with continuous hard shoulders.

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

Other upgrade
under motorway restrictions
Highway authority
Highways Agency


This scheme has been completed and we are no longer accepting progress updates.
16 December 2008

Preparatory works have started at the Berry Lane Viaduct, between Junctions 17-18. This is in advance of the main works which are scheduled to start in April 2009.

23 February 2009

Exhibitions are to be held in March 2009. Details have been published on the Highways Agency webite.

14 April 2009

Works signs now up - work starts on 27th April for 58 weeks. This is to widen the section between junctions 16 and 19.

23 November 2009

The majority of clockwise carriageway works have been completed. Clockwise structural works have now commenced and anticlockwise ground preparation is underway.

7 June 2010

The section between junctions 16 and 17 has been completed and is now back at NSL. The condition of the road surface is however somewhat shocking really.

13 June 2010

50mph section with average speed cameras now extends to approx 1/2 mile past J21 clockwise. Work is yet to start after J18 though. From the evidence of gantry base works between J21 and 23 it appears this section may only be upgraded with VSL and kept as dual three lanes.

12 August 2010

Junction 16 to 18 now completed, work started all the way around to junction 23. Most of the work is focussed on j18-19, though j19-21 is well underway. J21a-23 has only had a bit of work done so far.

8 February 2011

A committee of MPs has criticised the Highways Agency for not considering cheaper alternatives to widening such as hard shoulder running. The Agency was also criticised for taking too long over the procurement process (9 years) and for poor cost estimates. This mishandling has added an extra £1bn to the total cost of the scheme.

26 May 2011

The Highways Agency announces that work to widen the section between J21a-23 has now started.

25 June 2011

The work west of junction 21 is now mostly finished with the widened motorway fully open and just some tidying up to do.

15 May 2012

The 50mph temporary speed restriction was lifted today. The main phase of construction is now complete and the road is open to four lanes of traffic in both directions.

More information


With thanks to Si and Michael Pritchard for information on this page.