Britain has begun to accept bids for licences to explore for shale gas in more than half the country, three years after putting a stop to hydraulic fracturing because of the fracking technique's links to earth tremors.

The British government opened a round of licensing Monday, after Prime Minister David Cameron said his government is “going all out for shale” in an effort to boost Britain's energy self-sufficiency.

The licences are the first step in the exploration process but do not give outright permission to drill.

Oil and gas exploration companies must also obtain planning permission, environmental permits, and health and safety approvals before they can receive final go-ahead to drill in Britain, a process that means it could be five to 10 years before new drilling goes ahead.

“Ultimately, done right, speeding up shale will mean more jobs and opportunities for people and help ensure long-term economic and energy security for our country,” said Business and Energy Minister Matthew Hancock.

National parks protected

He said national parks and other important sites will be protected except in “exceptional circumstances.”

Three years ago, the government put hydraulic fracturing on hiatus, after two seismic earthquakes near Blackpool in northern England were caused by fracking.

Britain’s large environmental lobby has protested the technology, which involves injecting water, chemicals and sand into shale rock to extract the gas.

"The government has fired the starting gun on a reckless race for shale that could see fracking rigs go up across the British countryside, including in sensitive areas such as those covering major aquifers," said Louise Hutchins, a Greenpeace U.K. energy campaigner.

France and Germany have banned fracking because of public outcry about the practice and exploration company Cuadrilla Resources met with protests in exploratory drilling in Britain last year.

The British government hopes development of shale gas can curb its growing dependence on imports and help replace revenues from oil in the North Sea basin that is dwindling.

Cameron has said he believes protests will abate as people see that fracking is good for the economy.

Recently, the British Geological Survey put the shale gas resource at 1,300 trillion cubic feet, but there is little incentive for British landowners to allow exploration on their properties as they are not guaranteed a share of the findings. 

With files from Reuters, The Associated Press