SIR – Dave Parker says that I have not done my research and that no-one has supported me in refuting his views on ‘chemtrails’ (Letters, April 24).

If he were to do a simple search on Google for ‘chemtrails’, he would find a great many hits almost all of which have a heading similar to ‘chemtrails debunked’.

He would find also that the chemtrail story is almost 20 years old. If he were to search Wikipedia for ‘climate engineering’, he would find a well-reasoned article with links to reports published by NASA, the Institute of Mechanical Engineers and the Royal Society.

If he had an open mind, he would see that the whole idea of ‘chemtrails’ is nonsense.

Sadly, this is unlikely, and there is little point in arguing further because, as Goldacre noted, you cannot reason people out of positions they did not reason themselves into in the first place.

Ron Harding, Beck Houses, Bingley