The role of an MP is to serve the public like other sector workers and so they should be paid accordingly. If their pay rises had the same limits then they may get some idea of the impact of pay restraint on other people. The public may also  view MPs as part of a community that is there to help others rather than as the self serving elite, which is how MPs are currently viewed.

This would be easy and cheap to administer with no need for a special committee.