By Megan Lane BBC News Online

Jeffery Archer's prison diary reveals that despite crackdowns, drugs are rife in the nation's jails. Why can't the authorities stop drugs at the prison gates? Prison might seem like the ideal place in which an addict could go straight. Life is, after all, strictly monitored and inmates are away from the influence of friends and associates.

But drugs are rife behind bars, and have been for years. Those incarcerated may already have a drug habit - indeed, many land up in jail having broken the law in order to fund their need - and those who don't may look to drugs to ease the boredom and frustration.

It does the guards a favour to deal with people who just vegetate

Steve Taylor

In his prison diaries being serialised this week, the disgraced peer Jeffrey Archer tells of being offered drugs by other inmates; of guards and lawyers smuggling drugs in; and of prison officers complaining that human rights legislation prevents thorough searches.

Ex-prisoner Steve Taylor, a trustee of the Howard League for Penal Reform, says there are two main reasons that drugs filter in from the outside world.

"Prison authorities are not always as cautious as they could be in checking for drugs; and in some cases they are not going to be because drugs calm prisoners down. It does the guards a favour to deal with people who just vegetate."

Forming new habits

Mr Taylor served one month in a Yorkshire prison before being transferred to North Sea Camp - the open prison where Archer is doing time - for three months.

Detecting drugs

Heroin: one to three days after use Cannabis and cocaine: 28 days

Many of his fellow inmates at the more secure unit used heroin or crack cocaine. Not only are these drugs highly addictive, heroin disappears from the blood stream far quicker than cannabis - an important factor for inmates who face having days added to their jail term should they test positive for drugs.

From 1996 to 2000, prisoners have served an extra 525,870 days after taking a mandatory drug test. As the average cost of a year in jail is about �27,000, the Howard League estimates that this extra time has cost the taxpayer well over �30m.

Drugs behind bars are nothing new

Thus, some cannabis smokers switch to heroin inside and eventually leave prison addicted. A number overdose soon afterwards, as the heroin available outside is considered to be stronger.

The urge for a hit leads many to put their health further at risk, Mr Taylor says.

"After lights out, one way to communicate is to pass notes in an empty can. You attach the can to a string, swing it outside the bars and your friend catches it by sticking their toilet brush out.

"Well, it wasn't always notes in the can. I once saw a hypodermic needle being passed between at least 20 prisoners in this way."

Drug drop-off

While hard drugs are less prevalent in open prisons - the escape offered by heroin may be attractive to those inside a cell, but not to inmates allowed to work in the community - there is a problem with cannabis, ecstasy and alcohol.

Visitors may smuggle drugs inside care parcels

"These are easy to get hold of in an open prison. A public footpath runs right through North Sea Camp, and family members just dropped the stuff under a bush at night," says Mr Taylor.

"But the system in an open prison is one of respect. The prisoners realise that it's a comparatively good place to be, so even those who do things they aren't supposed to don't tend to abuse it."

Vicious cycle

The Home Office is taking steps to tighten security and provide treatment.

To help prevent drugs being smuggled in, visiting rooms have been fitted with CCTV, and drug dogs help search cells and patrol perimeter fences.

Assessment and treatment is available in every prison in England and Wales, and about 60 intensive programmes have been put in place since 1999.

Women, young people and ethnic minorities are particularly poorly served

And prison is no longer the sole destination for convicted addicts now that "drug treatment and testing orders" - strict community-based penalties - have been introduced.

But the Howard League is among those campaigning for more to be done for drug users, and for it to be done in the community rather than the criminal justice system.

"Simply punishing people who are offending to support a drug habit will not reduce this offending. Instead we support treatment programmes which address social as well as clinical need," says a spokeswoman.