thought police 
noun [treated as plural]
A group of people who aim or are seen as aiming to suppress ideas that deviate from the way of thinking that they believe to be correct: curse those politically correct thought police!...
- He shows that modern liberals act as virtual thought police to suppress ideas of which they disapprove.
- No, they are leading us towards becoming a third-world nation of thought police and mind control.
- Does this bill mean, for example, that the board can still communicate directly with its employees without the Minister's thought police intervening?