"It is self-evident that ministerial departmental policy cannot be regarded as disqualifying bias. One of the commonest administrative mechanisms is to give a Minister power to make or confirm an order after hearing objections to it. Procedure for the hearing of objections is subject to the rules of natural justice, in so far as they require a fair hearing and fair procedure generally. But the Minister's decision cannot be impugned on the ground that he has advocated the scheme or that is known to support as a matter of policy. The whole object of putting the power into his hands is that he may exercise it according to government policy."