Run, Cowards! You've Stirred the Lion.
At least Guy Fawkes had a genuine cause and the intestinal fortitude to face up to his actions: "On arrest Fawkes did not deny his intentions, stating that it had been his purpose to destroy the King and the Parliament" (Wikipedia). No coward there.
The Nazis even invented new munitions to conquer Britain in World War II yet still failed. Hitler took the cowardly way out, but he didn't slink around without an agenda.
The French may have a reputation of late (okay, the last hundred years) of not giving their all in battle, but at least they fought like men during the Napoleonic Wars.
Just because Spain caved to terrorists before their last presidential elections in March of 2004, do the terrorists honestly think that the United Kingdom will? Nearly everybody can beat Spain. Consider what Britain did to the Spanish Armada in 1588.
The only thing the terrorists did yesterday was to create more trouble for themselves. They will miss the day that they only had to watch the skies for the American Eagle. The British Lion is now stalking. Run, cowards, run.