Even in the 1930’s, traffic levels in south east Wales were such that the possibility of a Newport bypass was under active discussion.

Proposals published in 1938 by the County Surveyors Society and County Councils association for a national fast main road network included a south Wales route reaching well beyond Cardiff, but a route  line around Newport wasn’t determined until 1946. This was then protected from development, and early designs completed by Sir Owen Williams and partners.

Today little hard evidence has surfaced to verify exactly how the route was chosen, the extent of any objections, and whether – as local folklore still suggests – this road was planned as the first Welsh motorway. 

After the war the Ministry of Transport published its own 10 year national roads plan, which avoided mentioning motorways, but prioritised important schemes – including a Severn Bridge, feeding a high speed road ending at Tredegar Park west of Newport – today’s M4 J28.

Yet, with much bigger post-war priorities, neither Government nor County Councils had money for such ambitious roadbuilding schemes. Setting the scene for a saga which would steadily become familiar to drivers in coming decades, bypass, bridge and high speed road were shelved. 

By 1960, with traffic growing dramatically and dire road links into England threatening economic prosperity in south east Wales, a striking lack of joined up thinking permeated British road building policy. Despite the ministry’s 1946 plan for a high speed road ending west of Newport, as the Severn Bridge moved towards opening twenty years later, the motorway it carried was planned to end a long way east of the town, on the congested A48 Gloucester road at Crick. 

This was 13 miles short of the eastern end of the new Newport bypass, where work had started in 1960 to relieve by now critical bottlenecks affecting the town and the area around it. The newly established Welsh Office scored a decisive victory here in 1964, ensuring sanity prevailed by pressurising the Ministry of Transport into adding this ‘missing link’ high-speed dual carriageway onto the Severn Bridge project – finally connecting England with south east Wales. 

Down the road, running between today’s M4 junctions 24 and 28, and following the still-protected 1946 route, building the Newport bypass had proved challenging. It involved a new bridge over the River Usk, and a tunnel through the landmark Crindau ridge, on which stood much residential property (top).

A single tunnel was planned in 1946, but two separate bores were chosen in 1961, providing easier construction access, and convenient linking onto the new river bridge.

Sir Owen Williams and Partners gained the contract, beginning work in August 1962 with a pilot westbound bore, followed in 1963 by excavation of the main tunnels. Various trial rock borings revealed little hint of the geological ‘faults’ which resulted in several serious rock falls – and subsidence to residential properties above. 

Progress was patchy, with the unstable geology demanding some innovative engineering solutions, bringing inevitable delays. The project missed its May 1965 completion target, and ran well over the tendered £1,506,100 cost – over £29m today – ensuring tunnel problems, and issues affecting residents’ properties above, reached Parliament. In July 1966, answering a written question about other ways of traversing the Crindau ridge, the then Secretary of State for Wales, Cledwyn Hughes MP, stated: “Several alternatives were fully investigated before the decision was taken, and the unexpected difficulties and cost involved in constructing the tunnels do not outweigh the disadvantages of the alternatives.”

Reports suggest local residents saw things rather differently. Some houses atop the ridge were quite new, and their occupants were re-housed for months – at taxpayer expense – in nearby hotels. Legal questions over market values and adequate compensation rumbled on until 1969 – two years after the project was successfully completed – when five structurally damaged houses were finally bought by the contractor. 

At their opening in 1967, the 1200ft (365m) Brynglas tunnels entered history books as the only bored tunnels on British motorways, playing a key role in resolving Newport’s serious 1960’s traffic flow difficulties… for a while and passed the famous home of the Mole Wrench on left of this shot (below) with very light traffic!

The road and tunnels were designed as two lane dual carriageway throughout – entirely adequate for traffic anticipated when the route was chosen in 1946, but only crystal ball gazing would have revealed the remarkable daily traffic flows in this area 70 years later… 

Today the Newport bypass is a relic of the past: despite widening in places, and changes to accesses and junction layouts to ease congestion, for some years now it has frequently operated beyond capacity.

Yet the south Wales economy depends on it, further widening is impossible – and the Brynglas tunnels don’t meet current safety rules. As long ago as 1991, a new “M4 relief road” entered the Welsh Trunk Road Forward Programme, with a route south of Newport published in 1995. All possible alternatives were then scrutinised, considered and reconsidered, with manifold objections to every variation on a new bypass route. 

After years of discussions, surveys and consultations, the Welsh government – which once deemed this new road “unaffordable” – announced its preferred route in 2006. Eight years later, in July 2014, the Minister for Economy, Science and Transport revealed definitive plans for the M4 corridor around Newport. Consultation on these plans has recently led to announcement of an independent public inquiry, beginning this Autumn and lasting up to six months. 

This biggest Welsh roadbuilding project of a generation is currently costed at around  £1bn. If it gets a go-ahead, construction could start in spring 2018, with completion by Autumn 2021 – thirty years after first formal acceptance of the need for a new M4 relief road around Newport.

With that glorious phrase “all things in time” ringing in their ears, for drivers suffering a daily low speed grind on and near today’s Newport bypass, 2021 can’t come a moment too soon.   

© Dave Moss


A brief history of main road and motorway development in Wales is here:


The recent history of an alternative M4 Newport bypass development is here:


Early documents relating to the history of the first Newport bypass are archived at  the Glamorgan Record Office. Catalogues can be accessed via  http://glamarchives.gov.uk/

Search of the relevant archive is obtained via


DMAW – The Motorway Archive Trust Records 

1 – General administrative records and publication  3 – DMAW/1/3 

Amongst this collection specific records relating to the Newport bypass story include:

MAW/M4/A General
MAW/M4/B Junction 22 to 24— Newhouse to Coldra
MAW/M4/C Junction 24 to 28— Coldra to Tredegar Park (Original Newport Bypass)

There is an interesting feature on the Brynglas tunnels here:  http://www.tunneltalk.com/Fire-safety-Nov11-Brynglas-historic-design-and-construction-review.php

Work started in June 2016 on improvements to the Brynglas tunnels after a severe fire which lead to their week-long closure to bring them up to current safety specification levels. There is news and information on this topic here:   


The Welsh Government’s new M4 Newport Bypass scheme information pages (with links to all reference material) are here 


Book – The story of building the original M4 route in Wales, from the Severn Bridge to Pont Abraham (the M4 terminus at Junction 49 north of Swansea) 

Hawker, Brian, and Stevens, Howard. The Motorway Achievement: Building the Network:  Wales. 2010. Pub: Phillimore. ISBN 978-1-86077-590-1.

Dave Moss
Dave Moss

Dave Moss has a lifetime connection with the world of motoring. His father was a time-served skilled engineer from an age when car repairs really meant repairs: he ran his own garage from the 1930’s to the 60’s, while Mum was the boss’s secretary at a big Austin distributor. Both worked their entire lives in the motor trade, so if motor oil’s not in Dave’s blood, its surely a very close thing.

Though qualified in Electronics, for Dave it seemed a natural step into restoring a succession of classic cars, culminating in a variety of Minis. Writing and broadcasting about these, and a widening range of motoring matters ancient and modern, gathered pace in the 1970’s and has taken over since. Topics nowadays range across the modern motoring mainstream to the offbeat and more arcane aspects of motoring history, and outlets embrace books, websites national and international magazines, newspapers, radio programmes, phone-ins and guest appearances. Spare time: hard graft on the garage floor attending to vehicles old and new. Latest projects: that 1968 Mini Cooper S has finally moved again after 30 years, and when the paint is finished, the 1960 Morris Mini 850 will also soon be ready for the road again…

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