SIR – Keith Thomson (Letters, April 14) persists with saying that the supply of oil is declining, yet does not contradict the point I made regarding the Canadian oil field that can supply the whole world on its own for a hundred years.

He seems to combine hard to get, and more expensive to produce, with a shortage. These two are different ends of the spectrum.

My point is, and still is, that at present there is no shortage, and there is not likely to be for the next hundred years.

I, unlike Mr Thomson, am not such a pessimist, and believe that the oil companies will rise to the challenge of finding more oil as required.

This is what they have been doing up to now, why does he think they are not capable of continuing to do so in the future?

A G Goldsbrough, Leeds Road, Ilkley