Police are on the hunt for an 18-carat gold toilet stolen overnight from Winston Churchill’s birthplace.

Officers were called to reports of a burglary at Blenheim palace in Woodstock, Oxfordshire, where the loo – valued at £1m - was on display as part of a contemporary art exhibition, just before 5am on on Saturday.

DI Jess Milne of Thames Valley police said: “The piece of art that has been stolen is a high-value toilet made out of gold that was on display at the palace.

“The artwork has not been recovered at this time, but we are conducting a thorough investigation to find it and bring those responsible to justice.”

A 66-year-old man has been arrested in connection with the theft.

The burglary has left the palace with significant damage and flooding. The toilet, designed by the Italian artist Maurizio Cattelan, had been plumbed in and was available for visitors to use.

The golden lavatory, named America, drew large crowds when it was exhibited in New York. It had been installed in a wood-panelled chamber opposite the room where Churchill was born.

Blenheim palace is the ancestral seat of the Duke of Marlborough.

Ahead of the toilet’s installation, the duke’s half-brother, Edward Spencer-Churchill, founder of the Blenheim Art Foundation, said last month the lavatory wouldn’t be “the easiest thing to nick”.

“Firstly, it’s plumbed in and secondly, a potential thief will have no idea who last used the toilet or what they ate,” he told the Times. “So no, I don’t plan to be guarding it.”

The palace’s chief executive, Dominic Hare, urged anyone with any information about the theft to contact police.

“Following the Thames Valley police statement we can confirm ‘America’, the art piece by Maurizio Cattelan, has been stolen in the early hours of this morning,” he said.

“We are saddened by this extraordinary event, but also relieved no one was hurt. We are very grateful to our staff and to Thames Valley police for their rapid and brave reactions.

“We knew there was huge interest in the Maurizio Cattelan contemporary art exhibition, with many set to come and enjoy the installations. It’s therefore a great shame an item so precious has been taken, but we still have so many fascinating treasures in the palace and the remaining items of the exhibition to share.”

Hare said the investigation continued, but “it will be business as usual from tomorrow”. Blenheim palace was closed on Saturday.

Visitors to the palace had been given three minutes of solitude to test out the golden throne. The Guardian art critic Jonathan Jones has described the experience as “much like peeing on porcelain … but here, among all the photos of young Winston, it also feels like pissing on British history”.