Inspectors from the Health and Safety Executive (HSE) are at the scene of an incident at the Royal estate at Sandringham.
A spokesman for the HSE said:
No formal investigation has been launched, but we do have inspectors at the scene with police who are making initial enquiries.
More top news
Britvic has confirmed it is to close its factory in Norwich, leading to the loss of more than 200 jobs.
Olly Lee's amazing strike for Luton against Cambridge is November's Goal of the Month in League Two
Scattered wintry showers across East Anglia will become confined to Norfolk by the morning. Long clear spells developing.