Should I complain to the police?

Yesterday whilst driving on an A road at the 70 mph limit I was cut up by an unmarked police car which then caused me to have to take evasive action by going into the outside lane the car then tailgated me meaning that when it came to slow down to 40 mph It was likely that he would of smashed into the back of me. Because he continued to tail gate me I couldn't slow down. he followed me to a car park and made offensive comments. he was not using blue lights. Should I complain to the police that he was diving in a dangerous manner?