The general rule for employees: expenses: each and every holder: the nature of the expense not the amount
The restriction of deductions under the general rule for employees’ expenses in section 336 ITEPA 2003 to those expenses that each and every holder of an employment would have to incur relates to the nature of the expense and not to the amount. For example, if an employee needs to travel in the performance of his or her duties you cannot deny a deduction for rail travel because the journey could have been made more cheaply by bus.
This is supported by a comment of Lord Wilberforce in Pook v Owen (45TC571) on page 596. He said that the rule:
“is drafted in an objective form so as to distinguish between expenses which arise from the nature of the office and those which arise from the personal choice of the taxpayer. But this does not mean that no expenses can ever be deductible unless precisely those expenses must necessarily be incurred by each and every office holder. The objective character of the deductions allowed relates to their nature, not to their amount.”