TODAY Trinity House, the General Lighthouse Authority for England and Wales, is celebrating its 500th birthday.
Since being granted a Royal Charter in 1514, Trinity House has survived through civil war, two world wars, the Great Fire of London and huge changes in technology.
But 500 years on and the corporation, focused on the safety of shipping and seafarers, is still vital.
Staff at the Harwich centre work 24 hours a day all year round to keep lighthouses, buoys and lightvessels working.
After 4.30pm every day, they also take overnight responsibility for Scotland and Ireland.
If a light stops working, fails to turn or the radar signals do not transmit, they know about it.