Date and location of it makes me think it has to do with the Boudicca rebellion.
also from today (this isn’t the one I saw, but basically, the site described wasn’t previously thought to have been burned at that time):
http://news.bbc.co.uk/2/hi/uk_news/england/berkshire/8151385.stm
“They believe this, along with other finds, suggests the site could have been destroyed at the hands of queen Boudicca, who in AD 60/61 led a major uprising against the occupying Roman forces.”