One simple example: cheap gas will encourage the US petrochemical industry to invest $30 billion in new plant over the next five years, according to the Chevron Phillips Chemical Co. Plastics producers will get a double boost from cheaper feedstock gas — the raw material for their product — and lower electricity costs. This will further increase the American advantage over competitors in Western Europe and Asia whose usual feedstock is oil.

Thus shale gas has changed the game and not only in terms of hydrocarbons supply: it has provided the US with a chance to launch an economic recovery based on manufacturing and exports.

Americans have largely taken all this in their stride, even though as shale exploration moves into liberal north-eastern states a degree of nimbyism becomes apparent. How very different from the reaction in Britain where the prospect of a large new source of energy and exchequer revenue has either been ignored or treated with suspicion.

A lot of nonsense is talked about the prospects for shale gas in Britain, both for and against. Advocates claim that there are gigantic reserves just waiting to be tapped, and that the North American phenomenon could easily be replicated here. Opponents — and they are in the vocal majority — say that fracking (hydraulic fracturing)poisons the water supply and causes earthquakes; they also worry that renewing Britain's search for hydrocarbons will divert investment away from renewables.

The truth as usual lies somewhere between. The geological potential is certainly large, though the recoverable element of the gas in place has not yet begun to be assessed. A fundamental difference between Britain and the US is that in Britain mineral rights belong to the Crown, while in America they belong to the freeholder, which inevitably means British developments will take longer to initiate, even without political pressure from greens and local interests.