Commuters and tourists are advised to plan their upcoming journeys in advance, as Network Rail carries out upgrades to the Severn Tunnel.

From Saturday, May 23, passengers travelling between South Wales and Bristol may be affected.

Great Western Railway has said however that replacement services are in place to keep people moving throughout.

Nia Watkins, Network Rail Wales and Borders route Regional Asset Manager said: “Running beneath the Severn Estuary, the 4.35-mile Severn Tunnel is one of the most challenging environments on the UK rail network, making this work essential to maintain safe, reliable services and support its long-term future.

“Using an innovative solution developed by our teams at Network Rail, this complex and highly coordinated upgrade is being delivered at a world-first scale across the tunnel’s full length – making the railway more resilient and reducing the risk of future disruption for passengers and freight.

“Alongside this, we’re also renewing track that will serve the new Bristol Brabazon station, which will bring passenger services back to the Henbury and Portishead lines for the first time in more than 60 years, supporting local communities and economic growth.

“We recognise this work requires the temporary closure of the railway between Newport and Bristol Parkway, and we’re grateful to passengers and local communities for their patience while we carry out these important upgrades”

Passengers are advised to check their journey using the website or apps of Great Western Railway or National Rail before travelling, and allow extra time.

The Severn Tunnel runs beneath the Severn Estuary and is one of the toughest environments on the rail network. Moisture and saltwater have accelerated wear on the overhead power system since electrification, leading to more frequent maintenance and a greater risk of disruption.