Danny Alexander read out a blizzard of numbers yesterday to put flesh on the bones of the coalition's plans for capital spending on infrastructure. None of them was as significant as a figure he left out - the British Geological Society's latest estimate of Britain's shale gas reserves. The BGS says more than 1,300 trillion cubic feet of gas lie under Yorkshire and Lancashire alone.

The multiplier effects of big public spending projects on the wider economy are always uncertain. The effects of discovering a mother lode of relatively cheap energy on your doorstep are not.

The industrial might of the United States in the early 20th century was built on cheap domestic oil. North America's recovery since the 2008 crash - sluggish but still enviable by European standards - has been fuelled largely by the rapid exploitation of shale oil and gas reserves from the Dakotas to California. Their effect on domestic energy prices and American energy security has been so dramatic as to make a sideshow of President Obama's vision of a US industrial future based on wind turbines and solar cells.

A similar transformation of national energy supply is possible in Britain. It could create tens of thousands of jobs, boost tax revenues, improve a lopsided balance of payments, end British energy dependence on foreign gas suppliers and exert steady downward pressure on domestic prices.

The figures are compelling. The estimate of 1,300 trillion cubic feet is of "gas-in-place" rather than gas that is known to be commercially recoverable. But at the accepted US rate of 10 per cent recoverability, the figure still represents a 26-fold increase on the last BGS estimate for the same area from 2010. Even at an extremely conservative 1 per cent recovery rate, the figure means Britain has two and a half times more shale gas in what is known as the Bowland/Hodder formation than was thought three years ago.

And from the conclusion:

Without growth, every element of a spending review looks hopeful at best. With growth, hope begins to look plausible, and nothing underpins it more reliably than cheap, domestic energy. Greenpeace would naturally like the world to use less of it, but it has no monopoly on environmental concern and local gas is greener by far than imported gas, or coal. It is time to drill.

David Fuller's view We are all green at heart and Planet Earth needs some luck in terms of the rate of climate change. Meanwhile, we will all be better off by tapping our national supplies of shale gas, which has approximately half the CO2 emissions of coal, and lowering our energy costs in the process.

If more of our economies experience a satisfactory rate of GDP growth, there will be additional funds for vital scientific work, including addressing the challenges of climate change. Conversely, where GDP growth continues to slow, in part due to expensive and less reliable sources of energy, millions of people could easily be worse off than the likely consequences of climate change currently suggest.