The hike in methadone-related deaths in England and Wales last year could be a result of government policy to cut back on supervised consumption, PSNC head of NHS services Alastair Buxton has suggested.

Mr Buxton argued that growth in unsupervised consumption could have played a part in the 37 per cent rise in methadone-related deaths in England and Wales between 2010 and 2011, announced last week.

This could be a by-product of the coalition government's determination to see "a reduction in the absolute numbers of drug users", including methadone users, Mr Buxton said.

"That desire to push people through to a conclusion of treatment... I would question whether that has had some impact on the death rate" Alastair Buxton, PSNC

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"In the past few years, there has been a drive to move people from supervised consumption to them gaining trust… and hence being given custody of their methadone," he told C+D. "That desire to push people through to a conclusion of treatment, rather than stabilising them, has probably reduced the number of people being supervised, and I would question whether that has had some impact on the death rate." Methadone use fell 3.9 per cent during the same period in which related deaths increased, NHS figures show, but Mr Buxton pointed out that there was no accessible data about the volume of supervised versus unsupervised prescribing.

Martin Bennett of Wicker Pharmacy in Sheffield said half of his methadone patients were on supervised consumption, but suggested this was a higher proportion than in most other pharmacies. And he argued that more patients should be supervised, as the safety profile of methadone meant it was not "something that should be lying around at home".

The Department of Health declined to comment on whether it had a strategy to reduce supervised consumption, but said methadone deaths figures did not take into account whether methadone had been prescribed to the individual who died.

"Some people have suggested that one of the factors for this increase in methadone-related deaths is that heroin addicts have been supplementing ‘low-purity heroin' with methadone bought from the black market," a spokesperson said.

"This reinforces the importance of following national guidance on prescribing methadone so that it does not fall into the hands of drug dealers and the black market, where it can have fatal consequences."

Charity DrugScope backed the comments, suggesting that the number of fatalities could be linked to the "heroin drought".

"As supplies of heroin dried up, dropped in purity or became more expensive, dependent users turned to other substances, including methadone and benzodiazepines bought on the street," explained DrugScope chief executive Martin Barnes. "This explanation would be consistent with the fall in the number of deaths attributed to heroin or morphine, as well as the gradual increase in deaths linked to benzodiazepines since 2007."

Mr Barnes added that it was "crucial" for the government to continue funding a range of treatment options for drug addiction, stressing that there was no "one-size-fits-all" approach to overcoming dependency.