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.
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Showers easing with clear spells overnight. Strong winds easing.
Sunday forecast: Heavy rain is expected for a time with gusty winds, then clearing during the afternoon.
March in the Anglia region has been much drier and sunnier than normal although temperatures have been around average.