Why is OPEC’s oil production increase not calming prices?

From the BBC World Service: The group of major oil producing nations, including the likes of Saudi Arabia, agreed to cautiously increase production. They didn’t, however, throw oil out of the group, and oil markets today seem little moved by the news. We ask why. Also, as Jubilee celebrations continue in Britain – we’ll take you out to the world of cake, bunting and fizz at the U.K.’s street parties.