The 9.5m deep by 7.5m wide egg-shaped subterranean chamber would have been one of the biggest in the country when it was constructed in the 1780s, according to specialists from Mola, an archaeology consultancy that has been recording details of the rare find.
The cavernous brick-lined interior was used to store blocks of ice all year round, allowing the wealthy to impress their guests by continuing to serve iced culinary dishes during the hottest summer months.
Ice houses became popular among the elite in the 1700s but were also in demand from medical institutions and caterers, such as William Leftwich, who is recorded as using the ice house to supply the capital’s well-to-do.
The building is located in Park Crescent West in gardens behind houses regarded as a jewel of Georgian architecture designed in 1819 by John Nash, the architect of Buckingham Palace and Brighton’s Royal Pavilion.
Jane Sidell, inspector of ancient monuments at Historic England, said: “The Regent’s Crescent Ice House is a spectacular new discovery, astonishingly well-preserved and demonstrating the great engineering and construction abilities present towards the end of the 18th century.”
Originally ice was taken from local ponds and canals, but was seldom consumed directly because of its impurities. In the 19th century, though, an ocean-going ice trade grew up, bringing crystal clear blocks cut from the lakes of Norway to British ports, from where they would be brought to ice houses for storage, packed in straw for insulation.
When refrigerators came into use at the end of the 1800s, ice houses were left redundant, and many were filled in or used as garden sheds, fruit stores or wine cellars.
Historic England has designated the ice house as a scheduled monument and plans are being laid to allow public access via a viewing corridor.
Great Marlborough Estates, a high-end London property developer, is restoring the structure with advice from heritage specialists as part of a £500m redevelopment of Nash’s neoclassical design. The houses in the crescent were destroyed during the Blitz, unlike the ice house, and were rebuilt as copies in the 1960s.
Development work had required extensive research into the historical record, but it was only when archaeologists dug a trench across the gardens in 2015 that the intact structure came to light.
Grant Lipton, director of Great Marlborough Estates, said: “We always knew that Regent’s Crescent, given its existing historical status, would be an incredibly important development for us. Little did we know that we would discover one of the finest examples of a Georgian ice house in the country.”
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