Staff working at a psychiatric hospital near Cardiff went to a house party then tested positive for coronavirus, leading to others self-isolating and staff shortages.

Four staff at Hafan y Coed, the adult mental health unit at University Hospital Llandough, allegedly posted pictures of the party on Instagram. They then tested positive for Covid-19.

Another staff member, who asked to remain anonymous, said this led to 15 other people working at Hafan y Coed needing to self-isolate, meaning the mental health unit was short of staff.

Cardiff and Vale University Health Board confirmed that Hafan y Coed faced "challenges to staffing", but said the ward was still staffed safely.

A health board spokesperson said: "We are currently investigating the circumstances surrounding four members of staff who have recently tested positive for Covid-19 at our Hafan y Coed site, all of whom are self-isolating.

"While this has caused challenges to staffing, the ward continues to be staffed safely.

"Patient safety is our utmost priority and we have stringent processes in place across the health board to identify and isolate incidents, allowing us to continue to provide safe and effective patient care.

"Upon conclusion of the investigation, any staff believed to have acted outside of guidance will face appropriate internal health board action."

Last week South wales Police said they issued 31 fines after being called to five separate house parties across Cardiff.

Indoor transmission remains one of the key risks for the spread of Covid-19 — particularly since the new hospitality rules came into force in Wales last Friday, forcing pubs to stop selling alcohol and close at 6pm.