"It's too dangerous to go in at the minute, so we're carrying out fire investigation using other means talking to witnesses, interrogating systems that are functioning within the building, so the fire alarm, CCTV etc."
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Remaining dry with warm sunny spells on Monday.
Douglas Carswell told ITV's Peston On Sunday he wanted to "support" the government as a "critical friend" but refused to rule out a return.
The Ukip leader confirmed he had "no prior warning" of Douglas Carswell's resignation from the party as he hit out at the "staunch Tory".