Sir, I have just read Dr J. A. Woodcock's letter1 in the BDJ on testing and find that his proposal has one major flaw. As Prof Jason Leitch has said several times at the Scottish First Minister's briefings, if someone is tested today and the result comes back negative tomorrow, that only proves that they were negative today. It does not prove that they will be negative tomorrow, or on whatever date they may be given an appointment under Dr Woodcock's proposal. Regrettably, I cannot see, therefore, that his suggestion is of any help.