It’s an old favourite of the armed forces. If you want to learn a skill, say the recruiting ads - to become a chef, an HGV driver or a qualified electrical engineer - then join up without further delay.

With 30 per cent more cash being ploughed into prison education this year, and a new emphasis on giving offenders the skills that employers seek - even lining them up with jobs in some cases - one could be forgiven for wondering how long it will be before a short spell in prison becomes a wise career move for the young and unemployed.

“It is a very difficult balance,” says Martin Narey, who at 43 is the youngest ever director-general of the prison service. “I desperately do not want to tout for trade. I want a lower prison population. But I do reject entirely the notion that prison need always be a destructive experience. I think if we work hard enough, it can be a life-changing experience. A lot of people go through prison untouched by the experience, but many can come out with more life chances than when they came in.”

It was that “famous statistic” from the Basic Skills Agency that persuaded him of the need to tackle the unemployability of most prisoners. “The agency surveyed the prison population for us last year,” he says, “and told us that between 60 and 70 per cent had literacy and numeracy skills which were so low that they were ineligible for 96 per cent of jobs.

“We know from a huge amount of research that the single most important factor in stopping offending is employment, narrowly followed by having a home to go to. So our theory is that once we start to increase basic skills, we’ll find a large proportion of young people getting into jobs.”

It’s a theory that lies at the heart of the new director-general’s vision for the future of prison education, and it represents something of a break with the past. “We’ve always spent quite a lot of money on prison education,” he says. “But to be frank, it’s pretty impossible to identify any real outputs from that, and education departments have traditionally gone very much their own way.”

One worrying trend in the past, he says, has been for prison education to become largely recreational. “It’s not that there isn’t a place for pottery and things, but rather too much of it was being done in that way.” He also fears that some institutions have placed too much emphasis on providing education for more able prisoners. “It’s not a total exaggeration to say that there have been too many cases where there have been prisoners in full-time education doing their second degree, while prisoners who are largely illiterate have been working in the laundry.”

So in return for more cash, the emphasis will now be on basic skills. “What I have agreed with the Home Secretary, and he with the Treasury, is that, in return for this investment, we will reduce low levels of literacy and numeracy by 15 per cent over three years. That may not sound dramatic, but considering what we’re talking about here, it is, I think, a very demanding target.

“I think we’ll do it. And there are signs that at one or two places, such as Moorland and Huntercombe, we’re beginning to see early progress, with lots of young men getting NVQs at levels 1 and 2.”

At Moorland, a site just outside Doncaster which houses both young offenders and adults, and at Huntercombe, a young offender institution at Henley-on-Thames in Oxfordshire, the key to achieving measurable qualifications has been a three-pronged strategy. “First of all,” says Narey, “there’s the traditional classroom approach. That works with quite a few prisoners, but by no means all. A recent poll of young people aged 21 and under at Weatherby, one of our big young offender institutions, showed that more than half of them had been excluded from school by the age of 14. So a lot of them aren’t going to do anything in the classroom.”

The second approach involves training the more able prisoners to help teach literacy and numeracy skills to their fellows - a strategy which draws on the often-remarked-upon tendency of inmates to help each other, and one which has obvious advantages for both parties.

A third and novel way of tackling the problem is the training of PE instructors to teach basic skills. “Some of our most difficult young men, if they don’t do anything else in prison, they’ll always go to the gym,” says Narey, who spent most of the Eighties working at a borstal in the North East. “They effect a really good relationship with PEIs because PEIs can do a lot of things which appeal to young offenders.

“They’re physically very able, they’re good at sports, they’re very good at weights, they’re very fit. They are a real role model for a lot of young men. And so if we get them helping with literacy and numeracy, if it’s only making sure someone understands the chart of safety regulations in the weights room, then in the process of going to the gym they’re improving their reading and numeracy skills.”

But Narey is not prescribing all work and no play. “Recreation is very important, particularly with young men,” he says. “It’s important that they can get rid of some energy.” He believes it is possible to “cajole and persuade” them into the classroom through initiatives such as the Community Sports Leaders Award.”

As well as using PE instructors to teach basic skills, institutions like Moorland and Huntercombe have been taking education to the workshops, so that inmates can receive discreet help with their literacy and numeracy in the context of more “manly” pursuits such as laying bricks or servicing cars. And at the same time, the practice of paying higher wages to prisoners for “working” rather than “learning” is being discontinued. “It’s sometimes only 50 pence or a pound more, but when you’re earning pound;7 a week, that’s a lot,” says Narey.

Hard cash is a subject close to the hearts of many involved in prison education - a service which in recent years has found itself the first to suffer when governors have had their budgets cut. “Last year,” says Narey, “we had to find cash efficiencies of one per cent across the prison service. But all those efficiencies were fed directly into money which they gave us back to deliver the Government’s manifesto commitment on constructive regimes. So over the next three years, for education, offender behaviour programmes and reducing drug misuse, I’ve got an extra pound;225 million. And right across the estate, we did very well in terms of additional money, which is why we’ve been able to spend 30 per cent more on education this year than last.”

How soon will it be possible to tell whether the money is being well spent in terms of prisoners with skills, qualifications and, potentially jobs?

“The investment only kicked in this April,” says Narey. “But at Huntercombe, in order to try to see a year in advance whether we could make this work, we put the money in a year early. And the list of qualifications that young people are getting there is very impressive. In the six months up to April 1, about 240 boys got NVQ certificates of one sort or another, and that’s in a population of around 370.

“We put half a million pounds on their revenue budget - not just in education. And there’s been a remarkable transformation in the establishment, so that we will get that rare thing in a few weeks - an outstandingly complimentary report from the chief inspector about it.”

For the holder of what Jack Straw described (quite rightly, in the light of recent events at Wormwood Scrubs) as the most difficult job in Whitehall, that is probably worth half a million pounds in itself.