Owners of Renewable Heat Incentive scheme (RHI) boilers in Northern Ireland have lodged an appeal against a High Court decision that left them on reduced tariffs.

The challenge comes from the Renewable Heat Association of Northern Ireland as the inquiry into the botched “cash for ash” scheme hears more evidence of warnings missed by civil servants who admitted they were out of their depth and under pressure to get the scheme under way. One “whistle-blower” from an energy-efficiency company tried to alert minister Arlene Foster face-to-face but was fobbed off by civil servants.