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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Ukip has responded to the resignation of its only MP, Douglas Carswell, by suggesting he quit before he was kicked out.
A mostly warm afternoon but a fresh easterly breeze will bring a noticeably cooler feel along eastern coasts. Highs of 15 deg C (59 deg F).
ITV News Anglia's Political Correspondent Emma Hutchinson asks what next for UKIP after Douglas Carswell quits the party?