Magna’s plans to take a majority stake in GM’s loss-making European arm Opel triggered a backlash on Tuesday when German carmakers Volkswagen and BMW voiced unease over the deal and warned that they would review links with the Canadian car parts supplier.

Ferdinand Piëch, VW chairman, said that Europe’s largest carmaker would consider shifting business to other car parts makers after GM decided last week to sell a 55 per cent stake in Opel to Magna and Russia’s Sberbank.