BERLIN (Reuters) – German consumers must prepare for drastic electricity and gas price increases if the European Union cuts off Russian gas, E.ON Germany’s chief executive said on Tuesday, adding prices were already rising rapidly even without such a move. Speaking to German news organisation RND, Filip Thon warned that the energy firm was already seeing wholesale retail prices 20 times higher and electricity prices eight times higher this spring than a year ago. How much further prices would rise in the event of a ban on gas from Russia depended on the extent to which Germany increases its re…