Proposal to use Nazzano Method for Brynglas Tunnels solution

With a new Welsh Government now in place, this is an important moment to reassess the options available and ensure that public money is spent in the most efficient and responsible way. For many years, the argument has been made that a completely new motorway south of Newport - costed at approximately GBP1.5 billion - is the only viable solution to the bottleneck at the Brynglas Tunnels. However, this is no longer the case.

A proven engineering alternative exists that would resolve the capacity constraints without the need to construct an entirely new motorway corridor. That alternative is the Nazzano method of tunnel expansion. Originally developed and successfully implemented in Italy, the Nazzano method allows an existing tunnel to be widened while remaining open to traffic.

The technique involves constructing a new, larger tunnel shell around the existing bore, maintaining traffic flow throughout the works, and then removing the old lining once the new structure is complete. This method has been used internationally on busy motorway tunnels where closures were not feasible, and it has consistently delivered increased capacity with minimal disruption. The Brynglas Tunnels are an ideal candidate for this approach.

The surrounding geology is suitable for controlled external excavation, the existing alignment can be retained, and the method would allow the tunnels to be expanded to three lanes in each direction - the exact capacity required to eliminate the bottleneck. Crucially, this can be achieved without diverting traffic onto a new motorway and without the environmental impact associated with constructing a brand-new route across the Gwent Levels. Given the scale of public expenditure involved, and the Welsh Government's commitments to sustainability, minimising land take, and reducing carbon impact, it is essential that all credible alternatives are fully considered.

The Nazzano method offers a practical, cost-effective, and internationally proven solution that aligns with these priorities. I respectfully urge the Welsh Government to commission a formal engineering assessment of the Nazzano method as an alternative to the M4 Relief Road. This would ensure that decisions are based on the most up-to-date engineering practices and that taxpayers receive the best possible value for money.

Thank you for your time and consideration. I hope the government will take this opportunity to explore a modern, efficient, and far less intrusive solution to one of Wales's most significant transport challenges. Yours sincerely,

Simon Beddis,

Rhymney