On 24 June 1996, two days before England’s Euro96 semi-final, the Daily Mirror declared "football war" on opponents Germany. Beside a mocked-up photo of England's Paul Gascoigne and Stuart Pearce in World War II helmets was a parody of Neville Chamberlain's declaration of war from 1939, supposedly written by editor Piers Morgan.
After the front page was condemned by senior football figures—and earned a dressing-down from Mirror Group’s Chief Executive—Morgan issued an apology. But fears that the xenophobic language could encourage violence proved well-founded, and prompted calls on tabloids to tone down their coverage of future tournaments.
I was working at the Mirror at the time. Here is the story about how that front page came about.