The gas reserves in shale rocks in the UK have been “hyped”, a geology professor has warned.
Prof John Underhill from Heriot-Watt University said UK shale deposits were formed 55 million years too late to trap substantial amounts of gas.
He said the government would be wise to formulate a Plan B to fracking for future gas supplies.
But the fracking firm Cuadrilla said it would determine how much gas was present from its test drilling.
Hydraulic fracturing, or fracking, is a technique designed to recover gas and oil from shale, a sedimentary rock found worldwide.
The amount of shale gas available in the UK is acknowledged to be a great unknown.
Cuadrilla said estimates from the British Geological Survey (BGS) indicated a large potential gas reserve.