German Chancellor Angela Merkel said on Sunday that a tax on financial transactions would only work if it were introduced globally - but expressed little hope of the Group of 20 (G20) leading economies agreeing to this, dpa reoprted. She was speaking ahead of a crunch meeting on the so-called Tobin Tax by European Union finance ministers in Brussels on Tuesday. If trade unions were able to persuade G20 leaders to introduce such a tax, aimed at curbing speculation "then I will not oppose it," Merkel added. Merkel said Britain - which has opposed greater hedge fund regulation - would "unfortunately have to be overruled" at Tuesday's meeting. -- SPA