As JB said it is legal. In large companies or local council, they have a grading system and everyone on that grade is paid the same. I have worked within both and its very hard to get it right- Arse kissers tend gain more and the quiet suffer. I would first ask on how they judge each indivdual. I worked with a guy who was excellent at his job but rarely did a five day week!. I worked along people on a production line that were paid a different rate and the empolyer couldnt work out why they never worked as a team. My advice is try to get the company to give each of you 3.4% therefore what they lose on the swings, they gain on the Roundabout.