Fairground workers Shelby and William Thurston are on trial over the death of seven-year-old Summer Grant (Pictures: SWNS)

A young girl died when a bouncy castle that two fairground workers had failed to “adequately anchor” to the ground was blown across a park with her inside it, a court has heard.

Seven-year-old Summer Grant had been enjoying a family day out at Harlow Town Park in Essex when the inflatable was blown away, Chelmsford Crown Court was told.

Fairground worker William Thurston, 29, and his wife, Shelby Thurston, 26, both deny manslaughter by gross negligence and a health and safety offence.

Tracy Ayling QC, prosecuting, said Summer was with her father, Lee Grant, and other family members at Thurstons Fun Fair on Easter Saturday in 2016, and that Storm Katie was expected to arrive by Easter Monday.

View photos Summer died on Easter Saturday 2016 (Picture: PA) More

View photos Summer was killed when the bouncy castle she was in blew away at the funfair in Harlow, Essex (Picture: SWNS) More

“The weather was cold and windy,” said Ms Ayling. “Summer was playing in a bouncy castle that was one of the fair’s attractions run by these two defendants.

“While Summer was in the bouncy castle, it blew away from its moorings, bounced 300 metres down a hill; having hit a tree, it came to rest.”

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She said Summer was rescued from inside the bouncy castle and taken to hospital but died from her injuries.

The two defendants, of Whitecross Road, Wilburton, near Ely, Cambridgeshire, sat side by side in the dock as Ms Ayling opened the prosecution case on Tuesday.

“It’s the Crown’s case that they breached the duty of care they owed to Summer Grant by failing to ensure that the bouncy castle, called a circus super dome inflatable, was adequately anchored to the ground and failed to monitor weather conditions to ensure it was safe to use,” she said.

View photos Summer pictured with her mother, Cara Blackie (Picture: SWNS) More

Ms Ayling said Summer’s father had heard a scream.

“He turned and saw that the dome inflatable had lifted into the air, appeared to hit a caravan before flipping over,” she said. “He said ‘My daughter’s in there’.”

Mr Grant ran after it but it was moving too fast for him to catch it, Ms Ayling said.

Witnesses described seeing the bouncy castle “cartwheeling in the air, cartwheeling down a hill and only stopping when it hit a fence”.

View photos William Thurston and his wife Shelby are charged with manslaughter by gross negligence (Picture: SWNS) More

Ms Ayling said William Thurston was among those who chased the bouncy castle as it blew away and, when he went to help Summer, it appeared “she was very badly injured and struggling to breathe”.

Summer’s parents, who lived in Norwich, paid tribute to their daughter at the time.

Her mother, Cara Blackie, said Summer was a “bright, beautiful and most loving little girl”, and her father described her as the “most happy, polite and beautiful girl in the world”.

The trial continues.