The head of the ESB should reply to a letter from the trustees of the company’s pension scheme that stated it was “difficult to comprehend” proposals to pay a €400m dividend to the State when there is a €1.7bn deficit in the scheme and a serious risk to its future funding, a High Court judge has said.

Four ESB workers have brought a legal challenge over what they say is the “willful and deliberate” failure by the company to address a €1.5bn deficit in their pension scheme.