The future of oil

As Andrew Gray suggests ­(Letters, 17 December) shale was once the only source of petroleum oil produced in the UK. Before that, other fats and oils – some from whales and other marine sources – were used for lighting.

My letter (15 December) ­referred to a period when there was a considerable shale oil industry in Scotland which, among other things, produced petrol for motor vehicles.

By that time petroleum was being imported from elsewhere, mainly the Middle East, and ­refined here to produce petrol.

Petrol from shale could compete when taxed at the same rate as that from imported oil, but not when taxed at a higher rate.

I therefore repeat my statement that tax imposed by a UK government killed the Scottish shale oil industry.

How long that industry would have survived if the differential tax had not been imposed I do not know.

Remaining reserves of shale are an asset for our future if and when we need them.

David Stevenson

Blacket Place

Edinburgh