Members of the Armed Forces may be offered rehabilitation if caught taking class A drugs rather than being thrown out, the Ministry of Defence has said.
Some cocaine users will get the chance of rehabilitation
A spokesman said that despite the trial policy, taking drugs like cocaine and ecstasy would still not be tolerated.
But they said those of Lance Corporal rank, or equivalent, and below, may be kept on "in exceptional circumstances".
A tri-service programme assesses and educates those who test positive and meet strict criteria for retention.
The MoD's "open-ended trial" of the policy began in September 2003. A spokesman said they recognised that "a small minority of soldiers do take drugs" but that misuse was not widespread.
They said compulsory drug testing proved a deterrent, and that was run alongside a vigorous drug education programme.
"Appropriate action is taken against individuals who are found to be taking or supplying illegal drugs," the spokesman said.
"This usually means that they are discharged from military service."
However an "early intervention programme" now looks at educating and retraining those personnel who are kept on in the services.