“So long as the Secretary of State remains intent upon removing the person and there is some prospect of achieving this, paragraph 16 authorises detention meanwhile. Plainly it may become unreasonable actually to detain the person pending a long delay of removal (i.e. throughout the whole period until the removal is finally achieved). But that does not mean that the power has lapsed. He remains “liable to detention”…”
“…a provision which a) does not confer power to detain a person, but b) refers…to a person who is liable to detention under a provision…”
“The reference [ie to a person who is liable to detention] shall be taken to include a person if the only reason why he cannot be detained under the provision is that…”