The project's potential to provide 5% of total UK electricity demand from a renewable, British source will be examined alongside the impact on the natural environment, and social and economic aspects as well as the financing. The study will also look at the potential for other UK barrages.

"The Government will drive forward with delivering a step change in our use of renewable energy and will now start work on the feasibility of a Severn Barrage," said Hutton

"This is a truly visionary project, unparalleled in scale, potentially generating 5 per cent of the UK's electricity from renewable sources. As we undertake this work, we must understand the true environmental, social and economic impacts of such a project. They are potentially considerable.

"But so too is the challenge of climate change. And we must all have open not closed minds about how we meet the energy needs of tomorrow. "

Areas that study would cover include:

* Social and economic aspects, including public acceptability
* Environmental impacts and how these could be mitigated
* Financing, risk and organisation of such a project, including impacts on the energy market
* Technical and engineering aspects
* Regional impacts / infrastructure, including transport implications
* Planning, consents and other regulatory issues
* The potential for other UK tidal power projects