Jack Welch, the former head of General Electric, delivered a blunt rebuke to his handpicked successor yesterday, saying the failure of the conglomerate's earnings to meet market expectations last week was a "screw-up" that left Jeffrey Immelt with a "credibility issue".

Mr Welch's rare criticism of Mr Immelt, made yesterday on a television channel owned by GE, will increase pressure on the company's senior management to restore investor confidence in the US financial and industrial conglomerate.