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Section 2 - Gilwern to Brynmawr

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We are converting 8km of the A465 between the Glanbaiden junction at Gilwern and the Brynmawr roundabout to 2 lanes in each direction.

Traffic updates

Find out about road closures and traffic restrictions on the Traffic Wales website (external link). We also post details of the project on Facebook (external link) and Twitter (external link).

You can also find out about road closures, diversions, and project news by subscribing to Costain’s mailing list. Email Lauren Thatcher to subscribe.


Project status: Current
Region/county: South-east Wales
Start date: End 2014
End date: spring 2019
Cost: Total project costs circa £220m
Design and build contractors: Costain Ltd, with Atkins, Ch2M & RPS

This project is registered with the Considerate Constructors Scheme (external link).

Why we are doing it

The existing A465 was  built in the 1960s and is a single three lane carriageway with two lanes in the uphill direction and one in the downhill direction. A regional traffic study in 1990 identified the need to improve this road. This improvement to the A465 is critical to the social and economic regeneration of the Heads of the Valleys area.

The width of the road restricts traffic flow and opportunities for safe overtaking. In many areas there is poor visibility. Accidents on this stretch are concentrated around junctions and areas with poor visibility

This improvement to the A465 is critical to the social and economic regeneration of the Heads of the Valleys area. It will improve access to key services, jobs and markets supporting inward investment to areas such as the Ebbw Vale Enterprise Zone.

Current progress

Some of the construction progress to date includes:

2 new bridges at Glanbaiden roundabout have been completed and will be open to traffic soon.

The concrete arch bridge at Gilwern has been erected and the traffic is running through the arch. This bridge is the largest of its type in the world.

The footbridge at Gilwern has been lifted into place and will soon be open for use.

Extensive work has been carried out along the length of the scheme to steepen the surrounding ground and enable widening of the carriageway. 

The works have included the construction of 6200m of retaining walls to date and installation of over 6000 soil nails.

The 2 road bridges at Saleyard are nearing completion. These will be open for traffic use before the end of 2017.

A total of 33 diversions to Statutory Undertaker apparatus (water mains, gas mains, phone lines and electricity supplies etc.) have been completed. These have included major diversions work to two high pressure gas mains and a water main that required a new 1.5m wide, 100m long tunnel at a depth of 20m below the surface.

The treatment of a number of old mine workings uncovered near the Brynmawr junction.

The abutments for the Gateway Bridge at bridge at Brynmawr have been completed. Work will begin on the crossing structure at the end of Summer 2017.

Over 4000 trees have been planted within the scheme footprint.

The plan


Contractor appointed: 2011
Public information exhibitions: Throughout 2011
Statutory process to obtain powers to build the road: October 2013 – Dec 2014
Public local inquiry: March 2014
Construction began: End 2014
Completion: spring 2019
5 Year environmental aftercare and defect correction: 2024

How we consulted

We consulted on improvements to the A465 between Abergavenny and Hirwaun in 1994 as part of the process to develop the preferred route for the whole project.

In 2011 we held a series of public information exhibitions, presentations to local interest groups and meetings with local landowners and businesses We gathered information at these events to help the team understand how this section fit with local priorities, objectives and policies. This influenced the scheme design.

We held exhibitions of the draft orders in November 2013. These provided details of the final scheme which we then took through the statutory planning process.

An independent inspector held a public local inquiry in March & April 2014, where supporters and objectors to the scheme were able to present their case.

Alternative routes proposed by objectors were considered in a public inquiry alongside our published scheme.

Costain have a dedicated Community Manager and a Public Liaison Officer, Jeff Mapps, as part of their site team.

If you have a concern or query, you can contact Jeff Mapps by email:  or on 07739634021 or 0845 600 2664 (24 hours), email using our contact form.

You can also write to:

Costain Ltd
A465 Section 2 Project Office
Ty Gwyn Road
Twyn Wenallt
Gilwern, Abergavenny