A UK community radio station breached broadcasting rules after accidentally announcing the death of King Charles III in a May broadcast, the country’s communications regulator, Ofcom, has ruled.

Radio Caroline, a former pirate station that now mainly broadcasts rock music, apologised after pre-recorded messages falsely announced the King’s death. The broadcast was followed by the national anthem and about 16 minutes of silence before normal programming resumed.

Ofcom said the incident breached two broadcasting rules because of the “very significant inaccuracy” and the delay in acknowledging the mistake. One rule requires news reports to be accurate and impartial, while another requires significant errors to be promptly corrected on air.

The station explained that a staff member accidentally accessed sound files prepared for use in the event of the monarch’s death while carrying out maintenance on a studio computer. The files were played “out of curiosity”, interrupting the presenter’s remote broadcast.

According to Radio Caroline, the staff member panicked after realising the error and left the premises. The presenter, who was broadcasting remotely, did not immediately realise that the programme had gone off air.

The presenter eventually apologised about 30 minutes after the false announcement was first broadcast.

Radio Caroline said the staff member responsible had been reprimanded and had apologised. The station has also removed the pre-recorded death announcement files from its studio computer.