One fifth of convicts become hooked on drugs while behind bars, the Telegraph & Argus can reveal.

The Home Office has been forced to admit the shocking numbers - an estimated 15,000 based on 75,000 of the prison population being male - after questioning from Shipley's MP.

Home Office minister David Hanson said research suggests nationally one in five men - and fewer than one in ten women - who had used at least one of six drugs (cannabis, heroin, illicit metha-done, amphetamine, crack and cocaine) reported first using one of them in prison.

Shipley MP Philip Davies said it was "breathtaking" so many people could develop the habit in prison.

He said: "It should be the one place where this does not happen, where people are being watched. The Government should hang their head in shame so many people are becoming addicted."

Mr Hanson defended the figures and in a parliamentary written answer to Mr Davies added: "Research also shows the level of drug misuse falls dramatically compared with use prior to imprisonment and that prison is one of the key influences in getting people off drugs.

"Overall, prison contributes to a reduction in drug misuse for the majority of prisoners."

Work is under way in the district to encourage closer working between Bradford and Airedale PCT, Criminal Justice representatives and other partners to offer the support to people coming in and out of prison who have drug problems.

Liz Barrett, of Bradford and Airedale's substance misuse unit, said it was vital prisoners who were physically dependent on drugs received the correct treatment on release to ensure they did not get hooked again.

She said: "This is new work and talks have started. We are looking for personalised health care when people come out of prison which leads to safer communities.

"We want better data when people are coming out of prison, like a patient would have that had been in hospital. It is about joining services together. In prison there is a captive audience and people can be helped but they also need help when coming back into the community.

"There may also be people needing help when going into prison. We are starting to do some really positive work."

In June the T&A revealed junkie convicts made more than £130,000 in payouts for being forced to go cold turkey.

According to figures released under the Freedom of Information Act, last year there were 36 claims totalling £137,056 made to heroin addicts at Leeds Prison whose treatment was withdrawn or cut short while they were behind bars.