Twiggy Garcia tried the tactic Friday when he discovered Blair was among the patrons at the Tramshed in the Shoreditch neighborhood, the Daily Mirror reported. Blair was eating with a group of family and friends.
Garcia told Vice, an online magazine, that he put a hand on Blair's shoulder.
He then told Blair he was under arrest: "Mr. Blair, this is a citizen's arrest for a crime against peace, namely your decision to launch an unprovoked war in Iraq. I invite you to accompany me to a police station to answer the charge."
Blair declined the invitation, and his son called restaurant security. Garcia later resigned.