For years to which the current year basis of assessment rules apply, ICTA88/S110A (SAT1/184) provides that:
is deemed to have permanently discontinued the trade and commenced a new one. Tax is charged as though the change in resident status:
Despite the cessation and recommencement treatment, any losses
incurred before the change can be carried forward under ICTA88/S385
and set against profits of the same business.
As there is no provision in the Taxes Acts for splitting a
tax year in relation to residence, the deemed cessation and
recommencement should strictly take place at the start of the tax
year in which the taxpayer became resident in the UK or the end of
the tax year in which the taxpayer ceased to be resident. But under
ESC/A11, the business is treated as ceasing and recommencing on the
actual date of arrival or departure if the taxpayer so chooses and
the conditions of the ESC are met.
This rule does not apply to individuals carrying on a trade
in partnership, but there are instead special provisions on how
non-resident partners are taxed on their share of partnership
profits (ITH1664).
A copy of the guidance relating to pre-SA years can be
obtained from CT&VAT (Technical).