The benefits code: expenses payments otherwise chargeable to income tax
Section 70(5) ITEPA 2003
Expenses payments are not chargeable by virtue of Section 70(1) ITEPA 2003 if they are already chargeable by virtue of some other provision (Section 70(5)).
For example, a round sum expenses allowance is chargeable on all employees under Section62 ITEPA 2003 (Fergusson v Noble 7TC176) as earnings from the employment (EIM05100). So it is not chargeable under Section 70(1).
The distinction is important for PAYE purposes. Tax is deducted by the employer under PAYE from round sum allowances but not from expenses payments falling within Sections 70 and72, such as scale rate payments (Donnelly v Williamson 54TC636). See booklet CWG2.