(1)Except as otherwise provided, a person not domiciled in the United Kingdom at any time (in this section referred to as " the relevant time ") shall be treated for the purposes of this Part of this Act as domiciled in the United Kingdom at the relevant time if—
(a)he was domiciled in the United Kingdom on or after 10th December 1974 and within the three years immediately preceding the relevant time; or
(b)he was resident in the United Kingdom on or after 10th December 1974 and in not less than seventeen of the twenty years of assessment ending with the year of assessment in which the relevant time falls ; or
(c)he has, since 10th December 1974, become and has remained domiciled in the Islands and, immediately before becoming domiciled there, he was domiciled in the United Kingdom.
(2)For the purposes of subsection (1)(b) above the question whether a person was resident in the United Kingdom in any year of assessment shall be determined as for the purposes of income tax, but without regard to any dwelling-house available in the United Kingdom for his use.
(3)In this section " the Islands " means the Channel Islands and the Isle of Man.