Travel expenses: travel for necessary attendance: attendance for a temporary purpose: example
An employee is a safety officer. He regularly visits a particular factory every month to carry out a safety check. His responsibility for that factory has been a duty of his employment for a period already spanning twenty years (so it is not of limited duration). However, the tasks he performs on each visit are self-contained and the purpose of each visit, considered alone, is temporary. So a deduction is due for the full cost of his travel.
He visits the factory regularly for the performance of his duties. So it will be a permanent workplace if it is not a temporary workplace, see EIM32065. His attendance is not of limited duration (see EIM32080) but each visit is for a temporary purpose, see EIM32150. So the factory is a temporary workplace.