JAR-OPS 1
Readers of this thread might like to be reminded that what JAR-OPS 1 Subpart B prescribes is as follows:
JAR-OPS 1.085 (e) A crew member shall not:
(1) Consume alcohol less than 8 hours prior to the specified reporting time for flight duty or the commencement of standby;
(2) Commence a flight duty period with a blood alcohol level in excess of 0.2 promille;
(3) Consume alcohol during the flight period or whilst on standby.
Of course, any pilot must comply with whatever is in his employer's operations manual, which may also specify that the pilot must comply with local regulations (if lower limitations are prescribed). However, it is is extremely unlikely that a UK air operator that holds an AOC based upon JAR-OPS 1 would specify anything less than 0.2 promille.