If you want to get ahead - get a hat. Perhaps that old slogan really is true. Tom Cannon has more hats than Ladies Day at Ascot. And, following his roles as director of Manchester Business School, visiting professor at Kingston, would-be director of Everton FC, Management Charter Initiative boss, deviser of The Times university league tables, vice rector of an institution in Cyprus and many others he has taken up yet another position - as Mercers School memorial professor of commerce, he will be lecturing at Gresham College in November.