A police officer who tested positive for cocaine committed gross misconduct, a disciplinary hearing found.
Tony Mowling, a former PC with Essex Police, failed a drugs test in June and resigned before the hearing.
Essex's Chief Constable Ben-Julian Harrington, panel chairman, said it was "totally unacceptable" for officers to take illegal drugs.
The panel ruled Mr Mowling would have been dismissed without notice if he had not already left his job.
He was accused of breaching the fitness for work and discreditable conduct paragraphs of the standards of professional behaviour regulations and that it amounted to gross misconduct.
At the hearing, the allegations were found proven.
Mr Harrington said: "Illegal drugs destroy communities and ruin lives. Violence and exploitation go hand-in-hand with the sale of drugs and we work really hard as a force to tackle this."
He added that his force would not tolerate the use of drugs by officers or staff and such activities "undermine the trust our communities place in us".