Income Tax (Earnings and Pensions) Act 2003 section 336

Deductions for expenses: the general rule

Section 336 sets out the general rule governing when an employee may deduct expenses from their taxable earnings.

• An expense is deductible only if the employee is obliged to incur and pay it in their capacity as the holder of the employment, and the amount is incurred wholly, exclusively and necessarily in performing the duties of that employment.
• Other sections within the same chapter provide additional rules allowing deductions for specific categories of expense, as well as rules that prevent certain types of deduction — these do not depend on the general rule being met first.
• Where an expense qualifies for deduction under the travel expenses rules in sections 337 to 342, it cannot also be deducted under this general rule.
• The general rule has been the subject of extensive case law, reflecting how strictly the "wholly, exclusively and necessarily" test is applied in practice.