EIM63640 | Tax treatment of fire officers: full and part-time fire officers: non-taxable allowances
From HM Revenue & Customs · Employment Income Manual
The following allowances payable to both full-time and retained members of fire brigades are not chargeable to tax.
Subsistence allowances to cover the extra cost of subsistence during a period of duty, not exceeding 24 months, at a temporary station.
Free meals provided on duty and spoilt meal allowance.
A flat rate expense allowance is due where a fire officer incurs expense on the upkeep of undress uniform. See Booklet IR1 for amounts.