In prison, escape means different things to different people. Some find it in cigarettes, some in drugs. For other inmates the television in their cell is the only lifeline.

John Connors, a 42-year-old Dublin-born Traveller now incarcerated in Wormwood Scrubs Prison, in Hammersmith in west London, escapes through books. Unshaven and wearing gym trousers and top, he sits on a low bench in a cavernous room off a narrow landing. Connors speaks softly, intelligently and with more than a degree of charm.

The deep, wide scar that runs down most of his right cheek is a visible clue to a violent past. He is serving an eight-year sentence for a violent burglary in which he beat a man with a hammer.

He has spent a significant part of his life behind bars. “I served every day of a 12-year sentence for shooting. I lost remission because of fighting,” he says. “When I was left out, the probation service couldn’t do anything for me. I was back inside within weeks.”

He got another eight years for burglary and the assault, but he is determined this time to be out in four, by qualifying for full remission. So far, with the benefit of some medical treatment, Connors is on track.

One in 20 prisoners in Britain today describe themselves as Gypsy, Romany or Traveller. The real number is probably even higher, as many are reluctant to declare their background on their first day behind prison walls.

Self-harm rates are high in this group. The British department of health estimates that the suicide rate among male Irish Travellers living in Britain is three times higher than for the general population.

Why are so many Travellers in British prisons? Many say illiteracy is one of the principal reasons that they end up there, and that they struggle to cope once inside.

Nearly two-thirds of Gypsies and Travellers, according to a report by the Irish Chaplaincy Service for the Thames Valley Probation Service, have difficulty reading and writing, compared with just one in seven of their fellow inmates.

Born in St James’s Hospital in Dublin, Connors, who spent five years in a children’s home after his mother was jailed, learned to read during his 12-year sentence after another prisoner took him aside and told him he wasting his life.

Connors paid the prisoner, who was serving a life sentence, £8 a week to teach him over 14 months of study snatched during so-called association breaks. Today he spends some of his time writing letters for those who cannot.

“There are 10 Travellers on the wing,” Connors says. “None of them can read. I do the paperwork for all of them. Reading is the only escape I have. For the others, all they have is the TV. If they lose that, they are numb. There’s no point putting people into classes. They need to be taught in 10- or 15-minute snatches by people they know and trust.

“The education courses that exist are too much for them; the classes are too long. But they’re clever lads. If they could make better use of the stuff that brought them into jail they’d be fine, and they’d never end up here.”

Connors’s wife and family live a stone’s throw from Wormwood Scrubs, but he doesn’t allow them to visit; nor does he accept telephone calls or letters from them. “I’ve wasted enough of their years,” he says. “I want them growing up thinking that jail is a scary place.”

Connors sounds weary. “I’m tired of it all. Reading is an escape. The only way for the lads to make it inside here is through education. Outside, too, it is the same.”

Illiteracy is a drawback both inside and outside prison. In civilian life, literacy is more important than ever: you cannot take a health-and-safety course without it, for example, so building work is closed to Travellers. Everywhere, illiteracy is closing the walls around them.

Encouraging literacy Breda Power works each day with prisoners, encouraging those who can to take up literacy programmes. Her employer, the Irish Chaplaincy, set up by the Irish Catholic Church in the late 1950s, has devised books to encourage Travellers to start learning to read, with titles such We Are Travellers, A Traveller's Home and The Fight.

And the Shannon Trust, a charity set up in 1997 by a Sussex farmer, Christopher Mangan, after he became a penfriend of a prisoner, is working to recruit mentors to teach prisoners to read and write.

Culture is often a block. “Most Travellers want a job when they get inside – painting or other physical work – rather than being ‘put into education’. They want something that helps to pass the time,” says Power, who is well placed to appreciate the effects of incarceration. Her father, William Power, was one of the Birmingham Six, who spent 16 years in jail before the quashing of their convictions, in 1991. (They had been wrongly blamed for killing 21 people, and injuring 182, when two bombs went off in pubs in Birmingham in 1975.)

Sometimes, prisoners’ hopes of a job in jail are blocked because they cannot read. “They cannot work with cleaning chemicals, for example,” says Martin Maughan, who is being held on remand in Wormwood Scrubs.A Traveller who was born in Gloucester and lived in Oxford with his wife and children before he was arrested, he agrees with Power. “A lot of Travellers do not want to go to school when they are inside,” he says. “They want a job, a paid job.”

Education frightens Education frightens many Travellers. Some are unable to sit and concentrate for the duration of a class. Others shy away, embarrassed, because they struggle with the basic elements of the Shannon Trust's course.

Life inside British jails for illiterate prisoners is more difficult than it has ever been, as prisoners are expected to do certain tasks for themselves that require them to read. The system has become much more dependent on computers, and the number of prison officers – who might previously have helped inmates with the bureaucracy of prison life – has been reduced.

“There was a time when a prisoner could go to a warder and ask them to sort out visits or whatever. Now staff numbers have fallen, so people have less time, but everything has to be applied for in writing, so that makes life harder,” says Power.

Like many British-born Irish Travellers, Martin Maughan’s ties with Ireland are slender. “If I ended up in the docks in Dublin tomorrow morning I’d be nothing more than a tourist,” he says. “I’d be looking around wondering where to go. I was in Ireland for 11 months in 2001 and for a week in 2009. Sometimes they presume here that if you have an Irish accent you are Irish.”

In the past the British prison service made little effort to track inmates’ backgrounds. That has improved, although it is far from perfect. Many prisons now appoint dedicated Traveller diversity representatives, according to the Irish Chaplaincy. Prisons should “routinely ask” new prisoners if they are Travellers or Gypsies, it says, and “officers should ‘sell’ the benefits of being able to provide support such as regular Traveller group meetings”.

But even as extra efforts are being made to educate Travellers once they are behind bars, government cutbacks in the outside world are threatening attempts that have been made to overcome many Travellers’ reluctance to bet educated before they ever get into trouble

Complaining that services are being drastically reduced, or even abolished, Linda Lewins of the National Association of Teachers of Travellers says that 20 years of hard work are being pulled apart.