The government is sending the wrong signals to international investors in renewable energy after making a series of “substantial policy reversals”, according to the chief executive of E.ON’s clean energy division.

Speaking earlier on the first day of the Clean Energy Summit, Michael Lewis, CEO of E.ON Climate and Renewables, claimed decisions made by the Conservative government since May have resulted in the UK falling behind other global powers in its ability to attract investment.

“The UK has been E.ON’s largest market in terms of gross investment but since the election last year there have been a number of very substantial policy reversals here. This sends completely the wrong signals to investors.”

Lewis added that the removal of climate change levy exemption certificates for renewable energy – implemented in August 2015 – as well as changes to planning and the removal of technologies like onshore wind from the CfD mechanism have drastically changed how companies like E.ON view the UK market.

“It’s gone from being one of the most stable to one of the most risky in a very short period of time and I think if the UK is to continue vying for investment in renewables we really have to look at some policy adjustments,” he said.

Widening his point to Europe, Lewis added that new policy like President Obama’s clean energy plan means America now has “a clearer longer term perspective for building out renewable energy than the EU” for the first time in his career in clean energy.

“The reason the EU has been a leader in the last decade in renewable energy is because of the coherence of the policy and the direction all facing the same way. We see that fragmenting a little and that is to be regretted.

“It’s still all to play for but the EU generally and the UK specifically needs to come together and deliver some coherent policies across the renewable energy area,” he added.

Lewis’ comments follow months of criticism for the UK government over its changes to clean energy policy since May, with the Energy and Climate Change select committee concluding in March that investors had been spooked by recent policy changes.