Plastic bullets have never been used [against protesters] on mainland Britain.
(There is a huge student demonstration planned for tomorrow. so maybe I should say, “Plastic bullets have not been used [against protesters] on mainland Britain, yet.”)
Source: http://www.guardian.co.uk/uk/2011/nov/07/plastic-bullets-available-student-protests?INTCMP=SRCH
!Note – I had to change the text to this, as I was kindly sent a link that shows “baton rounds” have been used in individual cases.
http://www.telegraph.co.uk/news/uknews/1414224/Police-plastic-bullet-ends-siege-by-machete-man.html