The doctrine of legitimate expectation is a concept which has been evolved to exercise control over the discretionary power conferred on executive. This doctrine imposes a duty on public authority taking into consideration the entire relevant factor relating to such expectation. The origin of legitimate expectation can be traced in German concept of Vertrauenschutz – the protection of trust. Legitimate expectation includes expectation which goes beyond an enforceable right, provided it has some reasonable basis. Expectation may be based upon some express statement, or undertaking by or on behalf of public authority which has the duty of making the decision or from the existence of regular practice which the claimant can reasonably expect to continue. The basic principle of legitimate expectation was explained by Lord Diplock in Council of Civil Service Union V/s. Minister for the Civil Service.