But, we need to fashion a solution that will last—an M4 fit for future generations. And I just don’t believe that the proposed relief road will be anything more than an expensive stop-gap. In fact, as a policy approach, it manages to do something quite remarkable: it succeeds in both being outdated and premature at the same time. Outdated because the evidence of the last 50 years of transport policy is that building new roads, increasing capacity, only leads to more people using their cars, quickly filling up the new space. And premature, because it pays no attention to the game-changers coming our way. Now, I think it was Einstein who was meant to have said that the definition of insanity is doing the same thing over and over again but expecting a different result. In transport planning, we continue to do just that; we’ve become wedded to this so-called predict-and-provide approach, which, simply put, is that engineers predict that the traffic will grow in the future, so they build more roads to deal with it. And that’s a never-ending model of traffic growth, first set out 30 years ago, and, frankly, is nonsense.

Just think about it. If we were to take that to its logical conclusion and follow the trends, this approach has each of us earning an income of £1 million by the year 2205, and a lorry on the road for every man, woman and child. Now, aside from the pay rise, I don’t think this is a future that any of us want to live in and it’s certainly not the type of future we created the future generations Act to try and shape. Yes, there’s a problem at peak time around the Brynglas tunnels. Yes, something must be done about it. But we cannot build our way out of this problem. We’ve been trying that for generations and it doesn’t work. Traffic builds up, roads, once again, seize up and we rapidly find ourselves back at square one. If we’re not careful, we could end up with a £1 billion car park.

Already, the Freight Transport Association—the haulage industry lobby body—is saying that a new three-lane motorway at Newport will be inadequate to meet demand and we ought to be creating four lanes. Trying to relieve congestion by engineering ever bigger roads is no more than a short-term fix and an expensive one at that. The new stretch of M4 is currently estimated to cost £1,100 million for just 15 miles of tarmac. Bearing in mind that two years ago, people were insisting that the cost would be way below £1 billion, it may go up even further.

Yesterday, the Finance Secretary outlined the grim economic picture we face and how money will get even tighter in the coming years. Is it wise to tie up all of our borrowing capacity in one scheme in one corner of Wales? I ask my fellow Assembly Members: if the Government was to offer any one of us £1.1 billion to spend on something that would make Wales better, how many of us can honestly say that we would build a six-lane motorway over a protected wetland? Our entire line of new credit will be blown on a project that, in economic terms, will barely repay the investment over 30 years. Even using a formula that has been manipulated to exaggerate the benefits of road schemes, we’ll only see a return on investment of just £1.60 for every £1 spent, which the Treasury classes as low value for money. In that 30-year time frame, rapid technological development and a fully functioning metro project may well transform the way we travel.

Which brings me to my second point. We are trying to fit a fixed solution to a rapidly evolving problem. We’re so blinkered in our approach to transport management that we’re failing to look at the bigger picture, and there are substantial changes coming at us fast. If you speak to business people, they acknowledge that the world of work is changing quickly. Soon, we won’t need to be shuttling people back and forth between desks every day. Rapidly evolving technology means we need to be developing digital not transport infrastructure, but roomfuls of highway engineers in Cathays Park are never going to voluntarily face up to that. The formula used to justify a road as the best way to deal with congestion at the Brynglas tunnels takes the most optimistic view of the possible benefits. Meanwhile, the projections of the Cardiff metro take the most pessimistic view. Transport officials have suggested to the public inquiry that of the 11,000 journeys made every hour in peak times on the M4, the metro will, at best, only take 200 off the roads. I just don’t buy it. But even if this really is the case, if it will only have a minimal impact on rush-hour traffic, why are we not setting out to develop a public transport system that will tackle peak-hour M4 demand?

I fear this project, the metro, is being set up to fail. It’s being starved of investment by the UK Government cancelling electrification, and with the disappearance of EU grants because of Brexit, and by the road-building lobby who are trying to minimise its impact. It’s for policy makers to tell engineers what society needs, not the other way around. The other innovation that is upon us is the development of autonomous vehicles. We simply don’t know yet what the impact of driverless cars will be, but it is highly likely that this new technology, which will see cars driving side by side and bumper to bumper, will allow us to use existing road space much more efficiently, making the extra capacity unnecessary.

But perhaps the biggest development this approach fails to factor in is the law that this Government and this Assembly passed just two years ago: the Well-being of Future Generations (Wales) Act 2015. On 13 September, the Future Generations Commissioner for Wales—the person this Assembly empowered in law to be the independent watchdog of the Act—made a significant intervention. She said the Welsh Government, in its approach to the M4, was setting a dangerous precedent in its interpretation of one of our newest pieces of legislation. In its evidence to the public inquiry, the Government admitted the new motorway will cause harm. But, it argued, that harm is justified because of the immediate economic benefits it will bring—a good old-fashioned trade-off, or, as the Government QC beautifully put it, in a way that only a QC would, a balance between different desiderata.’

This, Llywydd, is the standard line: there are four elements to sustainable development, the argument goes. One of them is economic, and so a project that brings economic benefits is, by definition, helping to bring about sustainable development.

Sophie Howe’s challenge to the Government is that this is wrong as a matter of law. One pillar of sustainable development cannot override the others. Trade-offs are no longer lawful in Wales. Under the future generations Act, we can no longer bargain the long-term interests of future generations for the short-term benefits of today. I don’t see how an initiative that not only builds in traffic growth, but rises emissions for generations to come, whilst also saddling them with the costs, can be labelled as anything other than harmful for Wales’s future. This is a substantial challenge from the future generations commissioner, one I believe should not be confined to a debate amongst lawyers at the public inquiry, and today’s intervention was a catalyst by me to try and bring this debate onto the floor of our National Assembly, where it belongs.

Once the future generations Act became law, the Welsh Government should have looked afresh at the problem of congestion around the Brynglas tunnels and developed a solution consistent with all the principles of the Act, not just the one that suited its predetermined plan. And there are solutions to the problems of congestion. There’s lots of evidence of how improvement in public transport and, for short, everyday journeys, can cut car use, can reduce congestion, can alleviate pressure on the road network. On top of an ambitious metro project, congestion can be cut by a battery of interventions, and I just offer a few as an example—this is not an exhaustive list: bus priority lanes; traffic signals that give precedence to sustainable transport; park and ride; workplace car parking charges; targeted and tailored information about bus routes and times. Combining policies to encourage behaviour change with hard infrastructure to improve public transport has been proven to work. This is not revolutionary. This happens in successful cities all over the world. It’s just for the last 50 years we’ve turned our back on it, and now we’re paying the price, through poor air quality, congestion and the highest levels of childhood obesity in Europe.

There’s a way of tackling the problems on the M4 that does not harm the needs of future generations. In fact, it can help a whole range of policy interventions that we are trying to make work, and I would ask the Cabinet Secretary to quickly set up an expert group to find a solution to congestion issues on the M4 that doesn’t involve trading off the needs of future generations with the short-term aims of today. The public inquiry isn’t doing that. It’s looking at a series of road options to deal with the problem of congestion. And who have we asked to adjudicate the best answer? A civil engineer.

I would urge the Government not to reject the independent commissioner’s judgment on this. If they fight her in the courts, they risk undermining their very own landmark legislation we have told the world we are so proud of. We created this Act. It requires a new approach, not a retrospective defence of what we were planning to do all along. Diolch.