I was just getting comfy in bed last night (about 12.15) when I heard a noise. It sounded a bit like a low flying plane, although a bit close, but it went on for a fair while – 2/3 minutes.
So, just as I was going to get out of bed to see what it was, of course it stops.
Turns out a chemical plant about 10 miles away blew up. Thanks to Scott for the link : http://news.bbc.co.uk/1/hi/england/tees/5035918.stm