Fears over intermittent solar and wind power were "overblown" and those who said they would jeopardise Britain’s ability to keep the lights on have been "proved wrong", Greg Clark, the new business and energy secretary has claimed.

In his first major speech on energy since his appointment in July, Mr Clark set out his stall firmly in favour of green technologies, vowing it was "imperative" that Britain used "every industrial policy lever that we have" to hit its climate change targets.

While he acknowledged that the intermittent nature of wind and solar farms - which only generate power when the wind blows or the sun shines - was "creating new challenges for the system", he insisted that "the fears we had, even less than a decade ago, of the impact of intermittency - those fears were overblown".