In 2003, Cook resigned his post as leader of the House of Commons in 2003 to protest Britain’s involvement in the war on Iraq.
Here’s an excerpt from the Guardian’s obituary for Cook, who also served as a former foreign minister:
Cook was one of the very few contemporary politicians whose national reputation was built principally within the chamber of the House of Commons. He was a brilliant, coruscating debater whose most devastating performances combined lofty ridicule and forensic analysis in equal measure.