The man was working inside the trench in the village of Letterston when the sides caved in. A specialist rescue crew is at the scene, along with firemen and paramedics.
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Often clear skies this evening will allow for frost to develop. Low cloud will then roll in overnight, making the frost more localised.
Northampton Saints' Director of Rugby has denied that Wales international George North was knocked out during their game against Leicester.
Swansea defender Jordi Amat insists manager Bob Bradley has the backing of the players despite yesterday's 5-0 defeat to Tottenham.