Looking in to the details of the MOD PRP system, it appears that staff were effectively robbed of the pay increase they might have expected in the past with the promise of a performance based system that was designed not improve performance but instead, like all PRP system, was designed to save money.
When I worked at worked at Norwich Union in a team of 10 people, we were sold the idea of PRP being introduced that would "reward people for their efforts". When you looked at the system itself, it was nothing of the sort.
Of the ten people in a team, only a maximum of two could receive the top rating of "1", a further two could receive a "2" and three people could receive a "3", meaning that three people had to fight it out to get the remaining two "4 ratings, leaving one more person to get "5". Put simply, you were not and could not be rated on your performance because you were forced in to bands. if everyone in the team did the same work and every worked to the best of the abilities, one of those outstanding people would still have received the lowest rating of "5" whilst his or her colleagues, doing exactly the same work to the same standard could receive the top rating of "1".
In short, PRP is not a means of rewarding people for the work they have done. It is a means of paying people different salaries for doing the same job.
I know of a Council, for example, that allows its HR department to choose which council department should receive the highest "one off" performance bonus each year and, surprise surprise, the HR department wins the award almost every year.
So let's not criticise staff in the MOD for getting PRP. Let's castigate those morons who thought PRP should be introduced in the first place.