Dirk Simons, now chief financial officer of RWE Innogy, will become COO at RWE npower, while Martin Mikláš, now CFO at RWE Polska, will take over as CFO at the UK company.

RWE has made senior management changes at its UK subsidiary RWE npower, following unexpectedly negative mid-year results for 2015.

The company said: “We would like to thank them for their contribution toward moving npower from sixth to fifth in customer service and leading their work on digital”.

RWE this month reported its adjusted after-tax profit dropped 28% in the first half because of low power prices and problems at npower.

Big six energy company Npower has pulled the plug on its leadership team, with both chief executive Paul Massara and finance director Jens Madrian axed.

The poor results were partly blamed on a defective billing system that the company admitted may not be fixed until 2017, with regulator Ofgem having launched an investigation into the failings and expected to issue hefty fines.

New npower boss Paul Coffey said: “It is clear that RWE npower’s domestic business is not performing in the way that our customers, shareholders or our employees demand”.

RWE AG will promote Npower United Kingdom unit Chief Operating Officer Paul Coffey to the post of chief executive officer, replacing current head Paul Massara.

Mr Coffey was previously chief operating officer at RWE Innogy before transferring to npower in April.

Coffey has been with the RWE Group since its entry into the UK energy market in 2003.

In its statement on the board reshuffling, the company said it was working diligently to overcome problems particular to the British subsidiary by the end of next year.

The shake-up at the top of the firm comes amid continuing controversy over the sector.