A giant paper sculpture called Utopia turned into a nightmare when scraps of patients' private medical records were left flapping around Central Milton Keynes.
The recycling blunder left shoppers able see people's names, addresses and even what kind of operations they had.
Now MK Council chiefs, who commissioned the sculpture as part of the city's first Festival of Urban Living, has ordered the offending bales of paper to be removed.
And they have asked for the supplier, CS recycling, to hold an investigation to discover what went wrong.
Festival organisers had contacted the recycling company, based in Hertfordshire, when they realised they needed to protect the scaffolding around giant artwork from the winds in Midsummer Boulevard.
CS supplied 40 heavy bales of recycled paper, which were placed around the base of the sculpture.
But when scraps of paper broke free, passers-by realised they contained personal medical details - a recipe for potential identity fraud.
A spokesman for MK Council said today: “We were appalled to learn personal details were visible in a display of recycled paper. We immediately covered the bales and are arranging for their removal. We've asked the supplier of the bales to investigate, as it falls far short of our expectations.”
The Festival of Urban Living is designed to bring together artists, residents, architects, designers, urban planners and creatives for a free programme of exhibitions, discussions, events, creative workshops and performances.
Running from September 26 to October 13 on Midsummer Boulevard, it has been commissioned by MK Council, funded by Arts Council England, and is programmed and curated by experimental architectural practice raumlaborerlin.
The Utopia sculpture is the centrepiece of the festival and is described as a "triumphant, colourful tower, with far-reaching views" across MK.
CS Recycling say the paper bales had "only passed through" their depot after being processed by other companies.
"We bought this shredded paper in bales as waste paper, not 'paper for shredding', which is a key difference. To our knowledge the bales were 100% shredded paper and labels," said a spokesman.
She added: "CS Recycling was solely organising the recycling of the bales not the destruction of the data contained within the bales."