the blue book is the NAECI AGREEMENT which as AOM rightly stated is the agreement for most refineries and power stations it covers everything from rates of pay,travel money and digg allowance.
the agreement is constantly under threat by the big players who want rid before the new nuclear power stations builds really get under way,they also tried to bring in foreign labour but the strikes that started at L.O.R. and Staythorpe and then went nationwide on the NAECI sites put an end to that.