Edward Boyd is Deputy Policy Director at the Centre for Social Justice.

Prisons have a drug problem. Solving it should be a top political priority, as it will save thousands of people from becoming victims of crime, as well as billions of pounds.

The existence of a strong prison drug market has devastating consequences. It fuels violence in prisons. Drug-using prisoners suffer from physical and mental health conditions and their chances of rehabilitation are slim. Society suffers through addicted prisoners committing crime to fund their habits on release.

On top of this immense human cost is a financial one. Heroin and crack cocaine users are responsible for 45 per cent of all acquisitive crime in England and Wales (excluding fraud). This is estimated to cost £4.7 billion every year.

This is not a new problem. In 1994 John Major promised a “blitz” on drugs in prison. Similarly, the 1997 Labour Manifesto promised to “attack” the issue. Yet the issue remains: the prison service has become resigned to failure, resigned to widespread drug abuse being a daily part of prison life.

Today, just under a third of prisoners in England and Wales say it is easy to get illegal drugs. Seven per cent even say they have developed a drug addiction whilst inside.

New Psychoactive Substances (NPS) – often known as “legal highs” – are a growing part of the problem. Use of the most popular NPS, Spice, has skyrocketed in recent years with prison seizures increasing around 30-fold in just four years.

It does not have to be this way. Change is possible. A new CSJ paper, Drugs in Prison, sets out how. It requires a three-pronged attack.

First, prisons need to cut off the drug supply. Just 91 visitors and 615 prisoners were caught with drugs through searching last year, despite clear evidence that these are major smuggling routes. It is higher than a decade ago, but still far too low. We recommend that every visitor and prisoner be searched on entry to a prison. To stop drugs being smuggled in by corrupt staff – which was described to us by security officials as “a serious problem” – a tenth of prison staff should also be randomly searched every month.

Moreover, the way we search needs to be brought into the 21st Century. New technology – in the form of x-ray body scanners – has the potential to dramatically increase the effectiveness of searches by allowing prisons to identify drugs stashed inside body cavities. They have been described as a “game changer” in the US where they are now commonly used. The Ministry of Justice should urgently invest in these machines.

We also need to introduce Waste Water Analysis, which – as the name suggests – analyzes prison sewage to determine the level of drug use in prisons. It is very difficult for prisoners to “game” and will provide prisons with a good intelligence picture of drug use.

Secondly, prisons need to ensure drug users are identified and receive effective sanctions. Prisoners have a low chance of being identified as a drug user: the majority of prisoners will not be randomly tested during any given year. We recommend a quarter of prisoners are drug tested every month.

Tests must also include a wider range of drugs. It is not surprising that Spice use has boomed over this parliament – it is not being tested for. Yet a test for it does exist and recent legislative changes by the Ministry of Justice enable such testing.

We must also quicken the pace with which prisons respond to drug use. It can be months before a punishment is handed down to an offender following a positive drug test. This means that those on short-sentences can often take drugs with impunity, knowing they will never be punished. There is significant evidence from the USA that swift, certain and fair sanctions increase offender compliance and reduce drug use – we must learn from this and reform.

Thirdly – and most importantly – prisoners must receive the very best treatment to help them overcome drug addiction. To continually sanction prisoners without providing such treatment is counterproductive and unjust.

Too many prisoners are parked on substitute opiates, such as methadone, rather than being helped to live drug-free. Six years ago, 79 per cent of those on substitutes were being detoxified. Last year, it was less than a third. If prisoners are to lead a full, crime-free life on release then prisons must support them to become fully abstinent from all drugs.

This also requires strong links between prison and community treatment – all too often good work overcoming addiction in prison is undone when prisoners go back home. The Ministry of Justice has started this process by introducing “through-the-gate” pilots in the North East. We need more of this good work.

Reform in each of these areas is not just possible – it is necessary.

It is necessary for all those prison officials who are working hard to maintain a decent prison environment in difficult circumstances. It is necessary for those prisoners and their families who are faced with the destructive consequences of addiction. And finally, it is necessary for the thousands of people who become victims of preventable crimes every year at the hands of those desperately trying to pay for their drug habits.

Whoever wins the General Election in May needs to act on this evidence, improve rehabilitation and cut crime.