Recommendations include accelerating grid studies, streamlined consenting processes, early introduction of revised support mechanisms and, most importantly, strong political leadership.

The board has also advised the Government how the additional measures could go on to achieve the full 15% share required by the EU's renewable energy target.

In order to do this, experts in four sectors (bulk electricity, bulk heat, built environment and transport) were each asked to predict what could be delivered by 2020 with significant but achievable policy change. In total, the expert groups felt able to forecast bulk electricity could provide 7.1%; bulk heat could provide 0.9%; built environment 3.3%; and transport at 2.7%.

With a further 1% remaining, the report sets out three possible options but stressed that delivery of each will present further challenges to meet the ambitious proposed target.

* Installation of the Severn Barrage, half of which would count towards the 2020 target provided construction begins before 2016.

* A further 6GW of wind power, mostly offshore, bringing the total offshore capacity to about 24GW.

* A further 30% increase in energy production from renewables in the built environment sector. This would need to be retrofitted to existing stock, and would probably require installation of district-wide heat networks.

The report concludes that the 2020 target of 15% UK energy from renewables is achievable, but that rapid development of a transformed energy framework with radically new economic, political and social drivers is necessary. RAB also identified that renewables must be at the heart of energy policy and that many new policies are required and some, urgently.