work to rule
n.— «Teachers are now following the existing contract to the letter, a practice called “work to rule.” Teachers begin and end the work day specified in the contract and no earlier or later.» —“Westborough teacher contract talks heat up” by John Fenuccio MetroWest Daily News (Framingham, Massachusetts) Apr. 23, 2008. (source: Double-Tongued Dictionary)
Further reading
If someone urges you to spill the tea, they probably don’t want you tipping over a hot beverage. Originally, the tea here was the letter T, as in “truth.” To spill the T means to “pass along truthful information.” Plus...
When you had sleepovers as a child, what did you call the makeshift beds you made on the floor? In some places, you call those bedclothes and blankets a pallet. This word comes from an old term for “straw.” And: What’s the story...
This has been used, in England at least, for decades — at least since the 1950s when I first heard it, and I suspect much earlier. The derivation is from the union rule book.
I haven’t looked up any references yet, but I am sure they will be easy to find.