IAIN Lyall's letter (November 18) claiming that there is a very simple test to know if you are fit to drive - "don't drink any alcohol at all before driving" - has a flaw.

It says that if you are going to drive you must never drink, ever. I would like to know: if I had a glass of wine with my dinner two hours ago, am I fit to drive now? A simple home test, as suggested by Harry Morrison (Letters, Novem­ber 14), would be a worthwhile indicator.

George S Wright,

309 Main Road, Elderslie.