More money for the already bursting Exchequer? Possibly. When John Hume received the Mater Foundation gold medal at a dinner in the O'Reilly Hall, UCD, last week, he spoke of his idea for a certificate of Irishness. There are 70 million people around the world - 40 million in America alone - claiming to be Irish, and he suggests that this diaspora should be harnessed. His idea is that the Government - and guests Bertie Ahern and Mary Harney were listening very attentively indeed - should design a certificate of Irish identity and sell it, framed, for say $10 or $20, once the Irish link had been authenticated. While some might see this a very nifty money-raising exercise, Hume doesn't envisage a profit-making scheme; more a marketing one. By establishing the strength of the Irish diaspora, he says, we could become - in this now smaller world - one of the most powerful peoples on earth. The names and addresses of all these millions could be of great advantage to us as a market for Ireland abroad and for inward investment.