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Study maps fracking methane risk to drinking water

3 July 2014 Last updated at 19:29 BST

The British Geological Survey and the Environment Agency have mapped where key aquifers in England and Wales coincide with locations of shale.

The research reveals this occurs under nearly half of the area containing the principal natural stores of water.

The risk of methane being released into drinking water has long been one of the most sensitive questions over fracking.

David Shukman reports.