17Effect of becoming or ceasing to be a UK residentU.K.
(1)This section applies if—
(a)an individual carries on a trade wholly or partly outside the United Kingdom otherwise than in partnership, and
(b)the individual becomes or ceases to be UK resident.
(2)The individual is treated for income tax purposes—
(a)as permanently ceasing to carry on the trade at the time of the change of residence, and
(b)so far as the individual continues to carry on the trade, as starting to carry on a new trade immediately afterwards.
(3)But subsection (2) does not prevent a loss made before the change of residence from being set off under section 385 of ICTA against profits arising after the change.
(4)This section applies to professions and vocations as it applies to trades.
(5)In the case of a trade carried on by a firm, see sections 852(6) and (7) and 854(5).