Clarke suggested the government has to stay in the fight and does not support decriminalizing drugs, The Guardian reported. A number of high-profile advocates for drug law reform have emerged recently, including actor Russell Brand and Sir Richard Branson, chairman of Virgin Group.
Clarke said decriminalization would simply encourage more drug use.
"The government has no intention whatsoever of changing the criminal law on drugs," he said.
In his testimony to the home affairs select committee, Clarke acknowledged he has no grand plan.
"I have not reached the stage of that blinding insight about exactly how we are going to improve our record, is the honest truth," he said. "We have been engaged in a war on drugs for more than 30 years. We are plainly losing it. We have not achieved very much progress. The same problems come round and round."
Clarke said a proposal for a U.S.-style "drug czar" is not recommended because government departments have learned how to work better together.