Council of Civil Service Unions v. Minister for the Civil Service [1985]

Concerned, inter alia, the balancing of individual
interests against benefits and costs.
Minister issued order withdrawing from employees at
GCHQ right to belong to trade union.
No prior consultation with employees.
House of Lords held past practice of GCHQ generated
legitimate expectation that those who worked there would be consulted before
any important changes were made in their terms of employment.
Legitimate expectation may arise either from express
promise given on behalf of public authority or from existence of regular
practice which claimant can reasonably expect to continue.
Minister’s order was prima facie breach of natural
justice.
However considerations of national security outweighed
those of procedural fairness.