£30 BILLION plans for a barrage across the Severn estuary, from Lavernock Point to Brean Down in Somerset, are back in the spotlight this week, after Prime Minister David Cameron instructed officials to look into them.

The move follows a meeting between the PM and Peter Hain MP, who left his post as shadow Welsh Secretary in May to support the project which he called the 'single most important low carbon, renewable energy project in Europe'

Supporters of the scheme say it would provide 5 per cent of the UK's electricity and create thousands of jobs.

But environmentalists are against the project, which they say would harm local wildlife.

The UK government previously rejected plans for a publicly-funded scheme after a two-year feasibility study found the cost could be up to £34bn - double the initial estimate.

But it did not rule out private schemes, and last year, the Corlan Hafren consortium submitted a business plan to the Department of Energy and Climate Change outlining a new proposal.

It is understood that much of the funding would come from Kuwait and Qatar.

Mr Hain said on the weekend that he had held a ‘very good meeting’ with Mr Cameron.

"Government support is a pre-requisite for getting the whole project under way,” he added, saying it would be ‘transformative’ for Wales, and would create 20,000 jobs in construction, and ‘another 30,000 in activity around the barrage’.

A Downing Street spokesman confirmed that the Prime Minister met Peter Hain and Corlan Hafren last month, saying the government ‘is keen to promote a diverse range of energy supply and will consider the proposals carefully’.

But environmental groups are urging caution, including leading conservation organisation WWF Cymru.

Alun James, Policy Officer at WWF Cymru said: “On this latest barrage plan, our message to Government and the developers is clear – establish the facts and show us the evidence.

“We’re pleased that the Government is looking at renewable energy projects as an alternative to new fossil or nuclear power stations, but in the case of the Severn barrage, we want to see a lot more research carried out.

“There is a lot of work to be done – on the technology and on its impact on the local environment. The Government and consortium must be completely open on the new proposal and must disclose all research plans and findings.

“We support a major shift to renewables so that we can have an affordable, reliable energy supply as well as a healthy environment,” he added.

"However, if Severn tidal energy is to play its part, much more research is needed on the environmental impacts as well as on the different ways in which the power of the Severn could be harnessed.”

And following the latest development, the Wildfowl & Wetlands Trust (WWT) urged the government to take into account the findings of the earlier Severn Tidal Power Feasibility Study and ‘direct its efforts in further investigating new technologies’.

WWT Director of Conservation Dr Debbie Pain said: "The Severn Estuary with its incredibly large tides is absolutely the right place to be looking to generate tidal energy. However, that must not come at the expense of the natural environment.

"Thanks to the feasibility study we now have a wealth of knowledge about just what a concrete barrage from Cardiff to Weston would do to the environment of the Severn Estuary, and to people and businesses who use and value it.

"We haven't seen details of this new proposal from Corlan Hafren so we remain open minded. However, if it is still going to make a vast difference to the tidal range, it is going to change the estuary dramatically. That sort of damage simply cannot be compensated for elsewhere.

“The government would have to demonstrate that it is adhering in principle and practice to the legally binding EU Habitats and Birds Directives."

Speaking back in May, Gareth Clubb, director of Friends of the Earth Cymru, said Mr Hain was supporting the 'wrong option' for tidal power.

“A massive concrete barrage stretching across the Severn could have an enormous environmental impact, destroying vast areas of habitat of international importance," he said.

"Fish and bird life would be devastated and could not recover.

“Harnessing the power of seas around Wales is vitally important for tackling climate change and developing the green energy we need, and could allow Wales to lead the world in new marine power technologies," he added.

“But this project could well be the wrong solution – tidal energy can be captured by other means with much less damaging consequences, and could be giving us green energy far sooner than the 20 years it will take to build this barrage.

“Putting all our eggs into one risky project could block other better possibilities, and halt the growth in jobs and technology these could produce.”