Favoritism at the London NYC

I work at the London NYC I'm a union delegate and a very vocal one at that. My boss has had it in for me since I spoke out about how he favors certain supervisors. Since then he has targeted me and other employees who agreed he wrote me up twice in a week to try to fire me for infractions that his supervisors are equally guilty of. He follows me around to triple check my work meanwhile he wouldn't check anyone else to finds something wrong to try to write me up.

Response from Carl: It's interesting that your manager would go after you knowing that you're a union rep and presumably have a higher profile in the company than other staff who aren't actively involved in the union. I'd be interested to hear what your fellow union reps and managers feel about your treatment and if they've experienced the same thing and what their advice is to you.

Carl