The chief executive of Scottish and Southern Energy has called on the competition authorities to “look very carefully” at Centrica’s deal to buy 20 per cent of British Energy from EDF of France, because of possible effects on customers and competitors.

Ian Marchant told the Financial Times he was not saying the deal should necessarily be blocked but said it was an unfamiliar transaction for the UK, with potentially far-reaching implications, that “requires careful and detailed scrutiny”.