EIM32320 - Travel expenses: travel for necessary attendance: safeguards against abuse: journeys treated as private travel
Section 338(4) ITEPA 2003
In the same way that ordinary commuting is extended to include substantially ordinary commuting (see EIM32300) private travel is extended to include substantially private travel. The meaning of private travel is explained at EIM32180.
Substantially private travel means journeys where the business purpose of the journey is merely incidental to some private purpose, or the journey is made substantially for private purposes rather than business purposes. The effect of this rule is illustrated by the examples beginning with EIM32321.
You should not use this rule to deny a deduction where comparatively small sums and short distances are involved, see example EIM32325.
It is sometimes not straightforward to identify journeys that are substantially private travel. It is easy enough to identify journeys that are substantially ordinary commuting because you can compare the journey to the ordinary commuting journey, see EIM32300. You do not have the same point of comparison to identify substantially private travel.
As a result you may need to ask an employee about the purpose of particular journeys. Such enquiries need to be handled sensitively.