The long road to upgrading the A465 Heads of the Valleys Road

Set across six sections, the ambitious engineering project aims to convert 40km of road into dual carriageways.

The existing road between Abergavenny and Hirwaun in Rhondda Cynon Taff had been built in the 1960s as a single three-lane carriageway.

Three of the six sections have been completed, with a further two planned to start next year – but one section has been a source of contention more than others.

Work on the 8.1km Section 2 between Glanbaiden roundabout in Gilwern and Brynmawr roundabout began in late 2014, three years after the contract was handed to Costain Limited.

In 2013, a completion date of 2013 had been earmarked by developers but the project’s completion has been pushed back year on year.

The Welsh Government estimate that the £220 million project will be finished by spring 2019 – but fresh doubts have been cast on that estimate.

Last week, it was revealed that economy and infrastructure secretary Ken Skates had ordered a review into the Section 2 scheme.

A Welsh Government spokesman said: “The challenging nature of the scheme has meant that the programme for completion has been impacted.

“In light of this the cabinet secretary has ordered a comprehensive programme and cost review of the project to be undertaken.”

The announcement was criticised by Mr Skates’ opposite number, shadow transport secretary Russell George, but Welsh Conservative leader Andrew RT Davies has also spoken out.

He said: "Upgrading the road infrastructure around the Heads of the Valleys is essential – but one of the consequences of this is that many businesses in the area have been unable to acquire premises.

"Others, meanwhile, have been told they have to move. Many of my constituents are employed by these firms – and it is deeply worrying that they believe their future operations are under threat. "

The review is expected to begin “shortly” – but why was the scheme started in the first place?

Costain say the works are to improve the safety of a “notoriously dangerous road” and to help stimulate the local economy of Brynmawr.

The width of the road is said to "restrict traffic flow and opportunities for safe overtaking", while many areas have poor visibility.

Accidents on this stretch, which have included several fatalities, are usually concentrated around these low visibility areas or near junctions.

And while the finished product might well help boost Brynmawr’s economy, some traders living in the town are bearing the brunt of the scheme’s delays and constant road closures.

Gareth Thomas owns Thomas Waste Management Ltd, a Brynmawr-based skip hire firm right in the middle of the dualling works.

The 41-year-old told the Argus his business has been “suffocated” by road closures and project delays, leaving him no choice but to cut staff.

“A return trip to Abergavenny should take an hour but at times it has taken us two to three hours for one skip,” he said.

“We’ve been told to look at alternative routes, which for us means going up to Pontypool or across the moors which can add an extra 20 miles onto a trip.

“Our customers aren’t paying for the extra fuel. We are eating into our capital just to stay afloat.”

Monmouthshire county councillors for the Llanelly Hill ward - which covers Llanelly Hill, Blackrock, Clydach, Maesygwartha and Gilwern - have also expressed doubts about the scheme during their time in office.

Cllr Jane Pratt, who was elected as Conservative member for the ward in May, said: “I believe a review is long overdue.

“I think it’s interesting that his inquiry now being ordered by Ken Skates has been done without any debate in the Senedd.”

“I am the only councillor that actually lives in the project, I am 200 yards away from where they have recently been blasting the rock – I am right in the middle of things.

“Residents, businesses and farmers are really getting to the end of their tether.”

A similar stance is held by Llanelly Hill’s independent representative, Cllr Simon Howarth, who has been in post since 2004.

“I was at the public inquiry in 2013 and it has been a disaster from the start,” he said.

“It has had a massive impact on people’s lives here, it’s split the community and people are arguing amongst themselves. and as a councillor it’s ruined me.

“As a councillor it has ruined me. I’ve had so many complaints my life has been taken over by it.

“It’s not been fair on me, my family or the people of the ward.”

The term "rat runs" has become synonymous with the villages around the works, with both councillors and residents claiming that frequent road closures have led to cars using village roads as "cut through" diversionary routes.

But some progress has been made - two new bridges have been built at Glanbaiden roundabout and a new footbridge recently opened in Gilwern.

Also in Gilwern is the concrete arch bridge, which is the largest pre-cast overfilled arch bridge in the world.

Consisting of 70 pre-cast units, each weighing 28 tonnes, it is 52 metres long witha height of more than 6 metres and a span of around 29 metres.

Despite local opinion, Costain remain confident in delivering the "much-need" scheme with project director Bruce Richards eager to work with the Welsh Government while they undertake the review.

Mr Richards did concede that the project has been met with numerous "ecological, logistical and engineering challenges" since work began nearly three years ago.

"Construction is being carried out almost entirely alongside live traffic and runs through the steep sided and environmentally sensitive Clydach Gorge," he said.

"Difficult site topography, complex ground conditions, seasonal constraints and managing traffic to ensure the scheme is constructed safely are the major challenges."

In relation to the road's history of road traffi accidents Mr Richards said that road safety of commuters was Costain's "number one priority".

He added: "The provision of a dual carriageway with grade-separated junctions will make the road safer, especially avoiding head-on collisions, and will improve the resilience of the route if an incident does occur."