A woman has potentially life-changing injuries after an external staircase collapsed at a block of flats, police have said.

Three other people were taken to hospital with minor injuries after the incident in Carthew Terrace, St Ives, Cornwall, on Sunday evening, said Devon and Cornwall Police.

Helen Randall, who owns the property, said the stairs had collapsed when four members of her family were leaving after a visit.

She said her brother and his wife had been discharged from hospital while her mother remained at the Royal Cornwall Hospital and her aunt in Derriford Hospital, after they had all suffered broken bones in what she called “your worst nightmare”.

A spokesperson for the South Western Ambulance Service NHS Foundation Trust said the service had been called at 18:41 BST.

They said: “We sent four double-crewed land ambulances, two air ambulances, two first responders and an operations officer to the scene.

“We conveyed one patient by air ambulance to Derriford Hospital and three other patients via land ambulances to Treliske Hospital.”

Police said a scene guard remained in place and the Health and Safety Executive had been informed and would investigate the matter.