This was originally shown as a 3-part series on UK TV back in 1985. I can just about remember watching it then and have recently acquired it on DVD. There are no reviews yet for this title so here are my views.
This is based on a real drugs bust which took place in the UK in the late 1970s. The criminals were producing LSD on an industrial scale, much of it being produced in the unlikely setting of rural Wales, including the small town of Llanddewi Breffi a place name which would also receive widespread publicity years later when the 'Little Britain' comedy series featured it. The investigation took several years before the police were in a position to make arrests, and the cops were led by the maverick D.I. Dick Lee (played here by Colin Blakely). Indeed it his book of that operation on which this series is based. Viewers in the UK will no doubt note, as I did, the similarities between this real-life cop and the fictional D.I. Frost in 'A Touch of Frost' drama series (superbly played of course by David Jason).
The programs stay quite close to the truth though this is a drama rather than a documentary. There are also some amusing 'comedy' scenes e.g. at the start of program one where all the cops are watching film taken of a previous 'undercover' operation at a pop festival to glean information. All the female cops are topless to blend in with the hippies around them! The cast list is extensive and features a number of names who were to become more famous in later years. Lesley Nightingale plays Sgt. Julie Thompson after whom the operation was named. Belinda Lang plays D.C. Joy Brookes, several years before she became widely known in the UK on the 'Two Point Four Children' comedy series. The scenes switch almost continuously between outside locations when they are staking out the criminals and the police station where they discuss their plans.
This is worth seeing if you can get hold of a now-rare DVD. I'm not expecting it to ever be shown again on TV. The action is sometimes a little disjointed but the tension of the investigation's build up leading the final arrests is good. Overall recommended.