M4 Motorway

The M4 motorway links London with South Wales. It is part of the unsigned European route E30. Other major places along the route include Reading, Swindon, Bristol, Newport, Cardiff and Swansea. Originally referred to as the London-South Wales Motorway, the English section was constructed between 1965 and 1971, the Welsh section was completed in 1993 and the Second Severn Crossing opened in 1996.

The M4 runs close to the A4 from London to Bristol. After crossing the River Severn it follows the A48 through South Wales, using the Brynglas Tunnels at Junction 25a, Newport and terminates just north of Pontarddulais. The strip of land along the M4, with its towns and cities, is known as the M4 corridor.

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