German energy company RWE AG (RWE.XE) has warned it will significantly scale back its investment in Britain unless the government provides "desperately needed" certainty over energy policy, the Sunday Telegraph reports.

The U.K. paper reports that in a recent interview Paul Masara, RWE's U.K. representative and chief executive of RWE-owned npower, said investments would be scaled back unless there are propositions put in place to attract capital lenders into the market place.

Mr. Masara said further RWE investment in more gas plant was unlikely, but that the company would continue to invest in renewables, the paper reported.