Assistant Chief Constable Steve Cotterill said "please do not see these two arrests as the police inquiry coming to an end" and appealed to the public for additional information.
He said: "I need additional information from the public out there to really get to the truth to what was the reason behind that fire - whilst I know the cause I do not know the reason behind it and I'm still anxious for that information to come forward."
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The TV chef claims his father-in-law "forged" his signature to make him personally liable to pay £640,000-a-year rent on a pub.
Rain is forecast to hit most parts of the country this evening with a weather warning in place for Northern England and southern Scotland.