TOP prize in a prestige national photographic competition is a once in a lifetime opportunity to tour Severn Tunnel's Sudbrook Pumping Station.

The search is on to find the best photography of Britain's rail network as part of the Take a View Landscape Photographer of the Year Awards.

This year's prize for the Network Rail 'Lines in the Landscape' special award is Sudbrook's hidden gem.

This historic pumping station was built to remove water from the tunnel, including that from the Great Spring, which was discovered during tunnel construction in the late 19th century. The pumps now remove an average of 15 million gallons of water each day.

The station also provides access down a 180ft shaft, which leads to the complex underground culverts and sub-tunnels that form part of the engineering design which has kept the Severn Tunnel operational for the last 126 years.

David Higgins, Network Rail chief executive, said: "Every day for over a century the railway has helped people travel across the length and breadth of Britain. Those journeys can take people across spectacular structures such as the Royal Albert Bridge or Box Tunnel and where people can experience truly amazing views of the countryside and our cities.

"Network Rail has the special duty of protecting and promoting this legacy as well as building a modern rail network for the 21st century. We are proud to continue to support this competition."

Now in its fifth year, the competition is the idea of landscape photographer Charlie Waite, and the best images will be showcased at an exhibition at the National Theatre in London. The winner will walk away with £10,000.

Last year, the Lines in the Landscape special award received over 500 entries and Network Rail is keen to encourage more interest this year.

Entrants have until midday on July 15 to enter by submitting photographs of the British landscape. The competition is open to everyone.

Entries must be uploaded via the competition website, http://www.take-a-view.co.uk and">www.take-a-view.co.uk and full terms and conditions can be found on the site.