SOUTER Lighthouse, a landmark familiar to residents and visitors on the North-East coast on Monday marks exactly 150 years since it began its working life 1871.

Now under the care of the National Trust, when it was first built Souter Lighthouse, on South Tyneside, was a technological marvel of its age.

The coastline between the River Wear and River Tyne was treacherous to shipping, with submerged rocks and constant smog from local industry, claiming up to twenty ships a year. Trinity House, the organisation still responsible for lighthouses today, recognised that a new lighthouse was needed.

Kate Devlin, National Trust collections and house officer at Souter Lighthouse said: "We’re proud of the fact that Souter plays an important part in the history of lighthouses.

"It was designed by Sir James Douglass, who was engineer-in-chief to Trinity House, as the first lighthouse purpose-built to use an electric light.

"This was a huge leap as, at that time, lighthouses were usually lit with oil lamps. This new technology was very exciting and meant a brighter, more reliable light could be produced by an arc lamp. Basically, steam powered generators produced an alternating current which was forced to jump between two carbon rods, creating the light."

Douglass also came up with a pioneering method to divert the light that would otherwise shine inland and be "wasted". He used a series of prisms to make it shine from a window on the floor below the main lamp instead. The light guided shipping around submerged rocks in the bay south of the lighthouse.

The window was split into two colours, red and white. If the white light could be seen, the ship was safe. If the red could be seen, the ship was on course for the rocks. Visitors can spot the window near the top of the tower and know it’s no ordinary window.

Souter remained an operational lighthouse until 1988. It was taken on by the National Trust and opened to visitors in 1990.

Some facts about Souther Lighthouse

• Souter Point Lighthouse, to give it its full name, is actually built on Lizard Point. Souter Point was the original site identified for the lighthouse, but Lizard Point, a little further north, was considered a better site due to its higher cliffs. There was a problem though, there was already a Lizard Lighthouse in Cornwall, so Souter Lighthouse’s name stuck.

• Souter lighthouse cost £15,148 to build, which would be in the region of £7.5million today.

• The Optic, the glass lens at the top of the lighthouse used to magnify the light, is made up of 1008 glass prisms. This lens, like those in lighthouses all over the world, was designed by a man named Augustin-Jean Fresnel. Fresnel lenses are still used today, including in car headlights.

Souter Lighthouse is currently closed. Check for opening times.