We feel it essential, in this connection, to stress that our present defence against the "Fifth column" depends firstly upon the degree to which aliens and persons known to belong to subversive organisations can be adequately controlled by the police, and secondly, whether adequate legal powers exist to take precautionary action against individuals in the categories mentioned above ar any moment considered desirable. We fully realise that high political considerations arise in regard to taking firm action against aliens or interfering with the liberty of British subjects.