Drug treatment is the first step on the road to recovery from addiction - but not where the journey ends, Paul Hayes, chief executive of the National Treatment Agency for Substance Misuse, told MPs and peers.
He said the big challenge facing the treatment system in the next few years was to ensure that even the most entrenched service users had the opportunity to get better and overcome their dependency.
"Medical experts tell us it can take several years for heroin addicts to overcome their dependency. So it is hardly surprising that a large proportion of those in treatment - about 95,000 at the last count – had been on a substitute prescribing regime for longer than a year," Mr Hayes told the All-Party Parliamentary Group on Drug Misuse.
"What is less clear is the continuing value of treatment to the 35,000 people who have been on methadone for more than four years. For some, this is a triumph because the substitute prescription enables them to hold down jobs, lead positive family lives and have a stake in society. For others, however, it may be a tragedy, because they could have been helped towards recovery sooner, leaving both addiction and treatment behind to get on with their lives."
His remarks came ahead of the expected publication next month of a new Drug Strategy with an explicit focus on enabling more people to become free of their addictions, recover fully and contribute to society.
Mr Hayes said the NTA had presided over the expansion of a treatment system that was already more ambitious, with the numbers successfully completing treatment free of their dependency more than doubling to almost 25,000 over five years.
This momentum would be enhanced, he said, by the Government's decision in the spending review to bring together central funding streams under the Department of Health umbrella as part of the transition to a new Public Health Service, which will absorb the NTA in 2012.
"I am confident there will be enough money in the national kitty to deliver the ambitions of the new Drug Strategy next year. Having one pot with one purpose will enable us to better join up prison and community treatment, integrate treatment for drug and alcohol dependency, and rebalance community treatment to focus more on outcomes," said Mr Hayes.
"I am not so sure we will be able to rely on the very significant sources of local funding from councils and PCTs as in the past. However, any disinvestment at local level now would be a grave mistake, when local authorities are about to be handed a key role to develop and deliver local solutions to public health challenges like drug and alcohol dependency."