They have been warned, as always, not to rampage through the streets, destroying things and attacking people. But as England's soccer fans prepare to visit Germany for the World Cup this month, another item has been added to their long "verboten" list: Don't mention the war.

"It's not a joke," Charles Clarke, then the home secretary, warned at a pre-World Cup briefing earlier this spring. "It is not a comic thing to do. It is totally insulting and wrong."

That means, basically, no getting drunk and goose-stepping in a would-be humorous manner. No Nazi salutes. No shouting "Sieg Heil!" at the referees. No impromptu finger-under-the-nose Hitler mustaches.