Income: Employment income rules - Specific payments and benefits in kind excluded from employment income for tax credit purposes: Armed Forces Gratuities
The Tax Credits (Definition and Calculation of Income) Regulations 2002, Reg. 4(4), Table 1 (Item 7).
Food, drink and mess allowances, for the armed forces and training allowances and bounty payments payable in the consideration of the undertaking of certain training and attaining a particular standard of efficiency (within sections 297 and 298 ITEPA)
This is the same as the income tax exemption (see Employment Income Manual EIM50110).