It's NOT actually Griff's flag..it's the collective property of the Rabble.
For quite a few year we had a London based Swedish fan, who we all knew as Sven, for some reason(!), and he got it made. A number of us chipped in to help pay for it...it just happened that Griff looked after it because he had a bag it fitted in. he went most of the games, and he was happy traipsing round with it. He rarely bothers with it nowadays...don't think it's got anything to do with him doing his great, unsung voluntary work on the turnstiles, otherwise he would bring it to away matches.