German utility RWE has initiated a management shake-up at its UK subsidiary RWE npower following dismal half year results.

RWE npower saw its operating result for the first six months of 2015 fall by 60 per cent year on year.

RWE said that the outlook for the Supply UK Division “had to be corrected downwards considerably”. The parent company said the main drivers of the poor results were “process and system-related problems in invoicing to residential customers”.

Today RWE has unveiled a management overhaul at npower. Current chief executive Paul Massara and chief financial officer Jens Madrian will leave the company “on their own wishes and by mutual agreement”.

Massara – who took over from Volker Beckers in January 2013 – will be replaced by Paul Coffey, who joined npower in April from RWE Innogy, where he was chief operating officer.

Madrian will be replaced by Martin Mikláš, currently chief financial officer at RWE Polska, and Dirk Simons, currently chief financial officer of RWE Innogy, will join to become npower’s chief operating officer.

RWE chief executive Peter Terium said: “At this time we need a CEO at RWE npower who will focus on fixing the basic process improvements and has a track record of implementing operational process changes.”

He said the Coffey had “repeatedly demonstrated this expertise”.

Terium added that Mikláš and Simons were “two assertive and experienced managers who have demonstrated their operational strengths in their previous roles”.

Coffey said today that it was clear that “RWE npower’s domestic business is not performing in the way that our customers, shareholders, or our employees demand”.