Armed police are investigating what is being described as a "serious incident" at a travellers' site in Peterborough.
Three people have been injured, two of them seriously.
All three have been taken to hospital.
ITV Anglia has more
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Fog patches and extensive low cloud at first will steadily lift and clear.
A murky start with mist and fog then gradually clearing, although some eastern coastal districts may remain cloudier.
Isolated showers should die out through the evening to leave a dry remainder of the night.