So BP has posted 17bn in losses from the spill, 32bn in costs for cleanup, and 20bn for the escrow account, this totals to 69bn. BP has total assets of 240bn, making their debt to net worth ratio about 1/3. They face a very real threat, gulf coast operations account for a large percentage of their profits. If they decide to liquidate various operations around the world and then a deep water drill ban is still in place they will be looking at bankruptcy.
However, BP is responsible for a lot of pensions in the UK and thus we could be looking at UK's very own too big to fail.