MARINERS approaching the Dorset coastline will have noticed the lights have dimmed somewhat at Swanage’s Anvil Point lighthouse.

This is because experts at Trinity House – the organisation responsible for maintaining the UK’s 600 aids to coastal navigation – have reduced the light range of the beacon, or in other words, changed the bulb for something a little less bright.

Whereas earlier this month, the light beam operated 24-hours-a-day for an optical range of 24 nautical miles, now sailors can only see the light up to nine miles out to sea.

And the lighthouse, built of local stone and completed in 1881, will now only operate during the night.

Trinity House’s Vikki Gilson said: “Anvil Point lighthouse continues to provide a vital service to mariners and we still consider it necessary to keep the light operational.

“However, some changes were made to it earlier this month. The decision to make these changes followed a full review of all Trinity House’s aids to navigation in 2010 and a user consultation process.”

The lighthouse, which stands at just 12 metres high - relatively short compared with other UK lighthouses - was originally illuminated by a paraffin vapour burner.

It was opened by Neville Chamberlain’s father Joseph, the then Minister of Transport.

During the 1960s it was modernised and electrified, then on May 31, 1991 it was fully automated.

Today it is monitored and controlled from an operations centre at Harwich.