The AFPRB simply provides 'advice' and is mandated to take account of the money available. They cannot rubber stamp any Treasury decision as they have no authority to endorse Govt decisions, merely to follow them.
See the TORs below:
TERMS OF REFERENCE
The Armed Forces’ Pay Review Body provides independent advice to the Prime Minister and the Secretary of State for Defence on the remuneration and charges for members of the Naval, Military and Air Forces of the Crown.In reaching its recommendations, the Review Body is to have regard to the following considerations:• the need to recruit, retain and motivate suitably able and qualified people taking account of the particular circumstances of Service life;• Government policies for improving public services, including the requirement on the Ministry of Defence to meet the output targets for the delivery of departmental services;• the funds available to the Ministry of Defence as set out in the Government’s departmental expenditure limits; and• the Government’s inflation target.The Review Body shall have regard for the need for the pay of the Armed Forces to be broadly comparable with pay levels in civilian life.The Review Body shall, in reaching its recommendations, take account of the evidence submitted to it by the Government and others. The Review Body may also consider other specific issues as the occasion arises.