A colony of Mediterranean snails has been found at the UK's Cliveden House, where they have lived in marble-wrapped secrecy for a century. ( BBC )
The snails, never found before in the UK, apparently came from Italy in a balustrade bought by a Lord Astor, a former owner of the mansion.
There are thought to be several hundred of the 11mm-long snails at Cliveden.
John Profumo met model Christine Keeler at the Buckinghamshire house in 1961, which led to a political scandal.
Footballer Steven Gerrard married at the National Trust property last year.
Amidst all this activity - and the visits down the years of luminaries as important as Winston Churchill, George Bernard Shaw and Charlie Chaplin - the Papillifera papillaris snail has been a reclusive guest.
"They were found by a specialist volunteer who helps us clean the statuary in Cliveden," said the Trust's nature conservation advisor Mathew Oates.
"He went to a talk at the local archaeological society given by a snail specialist, mentioned his find, and it turned out he'd spotted the colony which had almost certainly been there since 1896," he told BBC News.
Common around the Mediterranean, this is believed to be the UK's only sighting of the species.
It was in 1896 that Cliveden took delivery of a travertine marble balustrade that now runs for about 100 metres along the top of the house's immaculately coiffured lawns.
"It was purchased and brought over from Rome by the first Viscount Astor," said John Bignell, visitor services manager at the property.
"He'd been an ambassador in Rome and was a great collector. The Villa Borghese in Rome, which he bought it from, now has a copy."
When the snails climbed on board is not known, although the balustrade itself dates from about 1816.
At Cliveden, they have lived in crevices in the marble and at the bottom of the balustrade.
"What they're doing, what they're eating, we don't rightly know, although it's likely they're feeding on lichen or algae growing on the marble," said Mr Oates.
"But what's important is they've also been found in two, possibly three other places at Cliveden, so all our eggs are not in one basket from a conservation point of view."
Over the years, the snails would have had the chance to witness a number of seminal moments in UK politics.
Nancy Astor, wife of the second viscount, was the first woman MP to take her seat.
In the 1930s, ministers, prime ministers and other dignitaries came so often to mull the issues of the day that the circle of habitues gained the sobriquet of the "Cliveden Set".
But the most notorious event was undoubtedly the meeting of Profumo and Keeler in 1961. The 18-year-old model and call-girl was having an affair with a Soviet military attache; and when she later started an affair with the cabinet minister, and he then lied to parliament about it, his fall was a matter of time.
Still owned by the National Trust, the house itself is used as a hotel. Its most famous recent visitor was probably Liverpool star Steven Gerrard who tied the knot there in June 2007, though whether he or his guests spotted the odd Papillifera papillaris is not on record.