restrictive practice

noun British

a trading agreement against the public interest
a practice of a union or other group tending to limit the freedom of other workers or employers

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012