HARWICH’S position at the mouths of both the Stour and Orwell estuaries has long made it an important strategic location.

As the only safe anchorage between the Thames and Humber, the town thrived as a port, but had also long been considered vulnerable.

Down the years, Harwich has been a target for invading enemies, suffering at least seven attacks in 50 years in the 1300s alone. It was clearly a place in need of protection.

During Henry VIII’s reign from 1509 to 1547, Beacon Hill, behind Barrack Lane, became the site for a small fort built to take advantage of views both inland and out to sea. A second fort was later added.

Andy Rutter, secretary of the Harwich Society, a history group which owns and runs heritage sites in the town, said: “Beacon Hill is a headland which stretches out to sea.

“It was a good place to defend the town of Harwich, as you could see enemies coming by sea and attack them.”

Further buildings went up on the site and in 1889, a whole new fort was built at Beacon Hill.

State-of-the-art at the time, it was practically invisible from the sea and armed with guns, mounted on platforms which rose from pits in the ground for 20 seconds, then dropped back out of sight after firing to be reloaded.

Mr Rutter said: “It was the latest design at the time.

“Underground rooms were made and then added to during the Second World War.

“They were particularly interested in making places they could take aim from.

“In about 1935, radar started to be developed at Bawdsey Manor, on the River Deben.

“A radar tower was built at Beacon Hill in 1941 – one of the first radar stations in the country.”

Unusually, for what was technically an Army base, the tower itself was operated by naval personnel.

The hexagonal structure was fitted with two 15ft scanners, one for transmitting and the other for receiving, and designed to detect marauding Nazi E-Boats – small, fast wooden vessels, which were the German equivalent of the British motor torpedo boats.

The radar had a range of 15 miles and is thought to have prevented attacks – not least because the E-boats learned how to detect radar signals so they realised they were being tracked.

The Harwich Society took over the three-storey radar tower – complete with some of its original wartime scanning equipment – ten years ago. It has since restored it and had now opened it to the public. The equipment had been pulled off the walls by would-be thieves, but proved too big to carry off.

Mr Rutter said: “We started on the top floor, where the scanners are.

“The middle floor has the readers for the scanner signals and the bottom floor housed the generators.”

As the last building to go up on the site, the radar tower sits on the edge of the much larger established Army base – an area the Harwich Society would dearly love to also take on.

The Army base closed in 1956 and was fenced off, but has since become a target for vandals.

Mr Rutter said: “The society started 40 years ago, we have been campaigning to get something done about the Beacon Hill site.

“It is unique. There are about ten or 12 buildings on a site the size of two football pitches.

“It didn’t see any action during the world wars, but it remains the biggest historical site in Harwich.”

Half of the fort site is owned by Tendring Council and the rest, including the main access road, is in private ownership.

The Harwich Society fears the fort buildings, which include a guardroom, storerooms, engine houses and observation towers, will crumble and be lost forever if something isn’t done to save them soon.

Mr Rutter added: “We restored the radar tower to show what could be done at the fort.

“Beacon Hill would involve an enormous amount of work. It would have to be done one building at a time – but it needs doing.”