There is growing weight being given to reports that the Italian car giant Fiat is on the point of buying a majority stake in the German manufacturer Opel. Neither company has commented officially, but a senior Opel union leader has confirmed a report in Der Spiegel that the two are on the verge of a deal.Elsewhere in the motor industry, Porsche has categorically denied rumours that its main shareholders are planning to sell-out to Volkswagen. The Financial Times and the Bloomberg news agency reported that a sale was being considered. But a spokesman for the legendary sportscar manufacturer called the reports “nonsense.” Any such deal would mark an extraordinary reversal in relations between the two. More than three years ago, Porsche started an audacious move to takeover VW, Europe’s biggest car-maker with a turnover roughly 15 times the size of Porsche. Porsche’s holding company now owns nearly 51 percent of VW, and has plans to increase its stake to 75 percent this year.