Iran has seized two Royal Navy patrol boats with fifteen sailors and marines on board, claiming that the craft were in Iranian waters. Meanwhile, Iran's President Mahmoud Ahmadinejad has suddenly cancelled his trip to New York, citing "America's obstruction in issuing visas," though one suspects a more immediate reason.
Clearly, Iran is trying to provoke the West into either reacting or backing down and now the ball is in White Hall's court. If Britain does not take this act of war for what it is and act accordingly, then we might as well trade in the white duster for a white flag.
Personally, I'm hoping for a quiet meeting with the Iranian ambassador that includes the words "regime", "change" and "Trident".