Those are the Caynton Caves in the grounds of Caynton Hall in Shropshire, England. Caynton Hall is the stately home of the Legge family. Despite lots of claptrap about the caves being ancient and having a connection to the Knights Templar, it’s believed that the interior carvings were commissioned by the soldier and politician General Arthur Charles Legge (1800-1890) in the mid-Victorian era as a “folly”. Historic England dates the complex as probably from the late 18th or early 19th Century, but Legge likely extended and embellished an earlier excavation since it’s within a disused stone quarry.
Those guys were trespassing. The caves are on private land and have been closed off to the public since 2012 as a result of vandalism. In 2017, someone unblocked the access point and intruded to take pictures which received wide publicity and further speculation about the purpose of the caves. There’s no evidence for them being anything other than a Victorian folly, although intruders have apparently used them for clandestine ritual gatherings in modern times.