Britain opens up to oil and gas exploration using the controversial fracking technique

Hydraulic fracturing, or fracking, is a controversial method of extracting gas and oil from shale rock deep below the earth's surface.

To opponents, it's a threat to the environment.

To its backers - including the British government - it could provide "greater energy security, jobs and growth".

That's why ministers are opening up about about half of the UK to fracking.

We discuss the pros and cons with David Hunter, an energy analyst at Schneider Electrics, and Simon Clydesdale from the environmental pressure group Greenpeace.