I want to start by setting the scene. The A432 M4 overbridge forms part of a key route from my constituency into Bristol. It was erected in 1966 when the M4 was built and is a post-tensioned concrete bridge. That is, it has high-strength steel tendons in ducts within concrete to which tension was applied after the concrete set, before they were anchored in concrete and the ducts filled in with grouting. I will come back to the problems of such bridges later, but for now the key point to note is that it usually takes around 16,000 vehicles a day over the motorway to the Wick Wick roundabout, where drivers can continue on the A432 into Bristol or take the A4174 ring road.
I say usually, because in June 2023 National Highways closed the bridge, having given 48 hours’ notice to South Gloucestershire council, of which I was leader at the time. In December 2023, after six months of investigations, National Highways announced that the bridge would have to be replaced and could not reopen in the meantime, and that the work would take between two and three years, backdated to June. At one point, an end date of 2025 was mentioned, but that has now become the spring of 2026.
The closure is having a massive impact on local residents. The official diversion is long, so many of the 16,000 vehicles are ending up on local country lanes such as Henfield Road, Ram Hill and Down Road. Even part of the official diversion route is only a C road. The council has put in extensive measures to improve traffic flow, but roads are taking loads that they were never designed to take. That is resulting in long queues, residents being unable to get out of their properties safely or at all, and more potholes and the edges of roads breaking up. Heavy goods vehicles are using roads with weight limits and there is no enforcement to stop them. Henfield Road and Ram Hill are in a quiet lanes scheme, where walkers, cyclists, horse riders and drivers are supposed to share the roads respectfully, but that is not happening.
The situation has also exacerbated flooding on Henfield Road, and high levels of traffic are pushing water on to people’s properties. That has left villagers feeling cut off, especially when flooding has taken other routes out of action. Further, when the bridge is demolished, which we are told is due to happen in March, pedestrians and cyclists will also be forced to divert.
Above all, people question the length of time that it is taking to replace the bridge. One wrote:
“For the past 16 months, we have had just one route to exit Yate to reach the city centre, which has been plagued by continuous temporary traffic lights—often two sets on Bristol Road. Why is it taking so long?”
Another said:
“When the bridge is eventually replaced, it’s likely to be the best part of 3 years to fix the issue. This is an utter embarrassment and quite frankly an absolute disgrace. The inconvenience this is causing to businesses, commuters and homeowners to name but a few is immeasurable. Those responsible for this debacle should hang their heads in shame.”
The closure has left the usually busy stretch of Badminton Road between Coalpit Heath and the bridge practically deserted, which has had a huge impact on local businesses. Kevin at the Bigger Eater burger van has been trading in that lay-by for 30 years. He provided a great service to local people during the pandemic, but the loss of passing trade because of the closure could be the final straw. There is also a kebab van in the lay-by in the evenings. Viaduct Café has lost 60% of its turnover since the bridge closed, resulting in its losing half of its staff. The premises where it is located have lost two business tenants. PM Autos, which services cars and has an agreement to take vehicles for their MOT to a garage in Downend on the other side of the closure, has to take a round-about route that adds significantly to the time taken and cuts into their takings. The Golden Heart pub has lost the passing trade of people deciding to stop for a meal on their way home from work. Heritage Sheds and Fencing has complained that potential customers are not sure whether it is still open; again, it is losing trade.
The impact on the local economy does not seem to be fully recognised. This is not something that businesses can reasonably insure against, yet when I wrote to the Minister I was told simply that there is no right to passing trade. In the same way that viable businesses needed help to see them through covid, these businesses need support to ensure that they survive this closure.
Although the bridge is the responsibility of National Highways, it has fallen to South Gloucestershire council to deal with the impacts that I have described on the local road network. I wish to put on record my thanks to the many officers involved for their efforts in responding to such an unexpected event. After initial monitoring, they put in place temporary measures, including traffic lights, road closures and temporary signage, and when it was confirmed that the road would remain closed for two to three years, they reviewed the existing measures and implemented more. Although some were funded by National Highways, others were deemed to be an “existing problem”—overlooking the fact that the closure is exacerbating those existing problems—or too far away to be related to the bridge, despite the fact that closing such a major route has ripple effects across the local road network.
Unfortunately, the measures that the council put in place are not enough, for example, to stop the HGVs using unsuitable roads, because any physical measures that stop lorries also stop buses, and the police do not have the resources to enforce the restrictions. For a long-term issue such as this, it is vital that the police have the resources to manage it. I also highlight the impacts on other council services: carers, waste lorries and so on all have to take longer routes
The council has been dealing with extensive communication from the public and liaising with National Highways, the police and bus operators, which has been a significant drain on resources in itself. One thing that I was determined to do when I became leader of South Gloucestershire council was improve communication with our residents. In the case of the bridge closure, that meant doing video updates in which we put residents’ questions to National Highways officers. At the beginning, it felt that getting information out of National Highways to share with the public would be a challenge, but I am pleased to say that it got on board with the updates, so much so that I understand it was considering rolling them out elsewhere in the country. Not only have the video updates continued with my successor, but National Highways has attended public-engagement sessions alongside councillors and council officers. Although communication cannot remove all the frustration and disruption, it is vital that people know what is going on and can get answers to their questions.
Why am I bringing what could appear to be a hyper-local issue to the House? I believe that there is a significant wider risk. National Highways manages 169 post- tensioned concrete bridges on the strategic road network in the south-west alone, and 1,195 nationwide. In addition, there are an estimated 675 that are the responsibility of 105 local highway authorities. Of those 675, research by the RAC Foundation in 2021 reported that a whopping 293 required intrusive inspections that could cost £100,000.
“CS 465 Management of post-tensioned concrete bridges”, a document I am sure we are all familiar with, says in its introduction that
“tendons can be vulnerable to corrosion and severe deterioration where internal grouting of tendon ducts is incomplete and moist air, water and contaminants can enter the ducting system.”
It goes on to say that
“construction practices and a lack of maintenance”
are the key factors affecting deterioration. In the case of the A432 bridge, workers discovered when they drilled through to the tendons that the grouting was missing.
CS 465 also explains that the problem with post-tensioned concrete bridges is that “safety critical defects in post-tensioned concrete are typically hidden, very difficult to detect and may result in a brittle mode of failure.”
Unfortunately, visual inspections alone will not give warning of imminent collapse, and intrusive investigations can be expensive and potentially damaging. If a problem is identified, these bridges have to be removed very carefully, as the tendons are under tension—if we think about what happens when we release a taut elastic band, we can see why that would be dangerous. With many bridges having been built during the height of motorway building in the ‘60s and ‘70s, it is entirely possible that this sort of major disruption is coming to many other communities across the country.
I come now to my asks of the Minister. Given the high level of disruption and the local dismay about the length of time the work is taking, will the Minister work with National Highways to try to bring forward the reopening of the road? Turning to the wider issue, what reassurance can the public have that all the thousands of post-tension concrete bridges in the UK are safe? What is the plan to ensure that that is the case, and has it been reviewed in the 19 months since this bridge was discovered to be failing? How will lessons be learned from this experience to reduce the time needed to replace other bridges that are identified as failing?
Will the Minister review how residents and businesses are supported and compensated when National Highways inflict significant disruption on them for an extended period? Will he also look at how the local highway authority is helped to manage its road network when impacted by a National Highways closure, and at how the police are resourced to help it to do that? Will he review how the assessment is made of which measures should fall within the costs ascribed to National Highways, whether an existing problem is being worsened by the closure, and how widely the impact is recognised, so that local highway authorities are not left with huge bills? Will the Minister consider the approach taken to communications in this case, and work with National Highways so that initiatives such as the video updates are rolled out to other incidents, to ensure timely communication with the public?
I have previously spoken in this House about the financial challenges facing local authorities in simply trying to maintain basic infrastructure, even without additional problems such as this road closure. Will the Minister commit to giving South Gloucestershire council the money that it needs to restore the damaged roads when the bridge has reopened?