Britain’s oldest Jewish cemetery outside London has been granted Grade II listed status, after heritage chiefs confirmed that the first stones were laid 273 years ago.

Records show that the earliest burials at Plymouth Hoe Old Jews Burial Ground took place in 1744, after Jews began moving to the port town to supply the Royal Navy with tradecraft such as tailoring.

There are two Jewish cemeteries in Plymouth, but the Jewish Burial Ground on the Barbican, which has just been given special status, has been described as “hidden behind an old wooden door and surrounded by high stone walls”.

Until last year, it had always been hidden from public view, accessible only through a black door in an otherwise anonymous Barbican wall, “unloved and overgrown” until Jerry Sibley, the non-Jewish caretaker of Plymouth Synagogue, started investigating.

“I was really awestruck,” said Sibley. “The whole thing was like a wildlife park, completely overgrown, not just at ground levels but the height of it as well.”

Sibley, who looks after what is thought to be the oldest Ashkenazi shul in the English-speaking world, says that, were it not for his love of Star Trek, the burial ground may still be as he found it.

“When I looked around at all the stones it was all in Hebrew. It was really interesting because I’m not Jewish, so I don’t read Hebrew and I certainly don’t speak Hebrew, but when I was going back along the back wall I saw the sign of the Cohens on one of the headstones.

“Of course for me this relates to Star Trek, and I really could not understand at that point why there should be Spock’s ‘Live Long and Prosper’ symbol which comes from the 1960s on a headstone that dates back to the 1700s.

“It was that story there that really enthused my ambition to go and find out a little bit more about what it is doing here.”

Historic England took the decision to list the site after local “rediscovery” work that involved clearing the vegetation, prompting Plymouth City Council to apply.

Plymouth Councillor Patrick Nicholson said: “I’m so pleased with this listing especially as the decision recognised that this is one of the earliest Jewish burial grounds in the country. It’s a fascinating place and one which helps explain Plymouth’s story. To have it confirmed we have one of the oldest Jewish burial grounds helps celebrate our rich history.”