Judicial Review of Govt Acts - used to challenge a govt action on the grounds of illegality, ultra vires (acting without having the legal power to do so), unreasonableness, maladministration (not decided or carried out properly) and breaching the Human Rights Act. Courts can strike down the action (reverse it), award damages or force the govt to make the decision again, but properly e.g. overturned the block on Heathrow's third runway. Laws can't be struck down,