168.Section 46 provides that the detained person must be released on bail unless one of the exceptions to the general right to be released on bail applies or the court has imposed a requirement under subsection (1) of section 47 which has not been met. The exceptions to the general right to be released on bail are set out in subsections (2), (3) and (4). Under subsection (2) the court need not grant bail if it is satisfied that there are substantial grounds for believing that one of the exceptions in that subsection applies. It will be for the Home Office to show, on the balance of probabilities, that there are substantial grounds for believing one or more of the exceptions apply. Subsection (4) provides an exception to the general right to be released on bail for those subject to deportation on conducive grounds in the interests of national security.