David Blagdon has been in prison for 16 years because he damaged an empty church. Jason Bennetto finds out why It was on Friday 7 July 1978 that David Blagdon, aged 27, committed the crime that was to condemn him to a life sentence.

Blagdon began the day by stealing a bicycle from outside a shop in Oxford. He rode along the A34 to the first group of houses he reached - the small commuter village of South Hinksey. Here he picked up a rock and hurled it against the door of St Laurencechurch. Armed with a box of matches he went inside. Checking that the building was empty, he set light to some velvet curtains by the pulpit and another pair by the door. As smoke started to waft from the church he left and sat in the graveyard to wait for the police and the fire brigade. When questioned, he told officers that he wanted to be arrested. Later he described his actions as a "cry for help".

On 1 November 1978, at Oxford Crown Court before Judge Young, Blagdon pleaded guilty to arson and was sentenced to life. Now 43, he has served 16 years, three months and six days in prison, longer than most convicted murderers and terrorists, for causing£1,270 worth of damage in an empty church. According to law reformers, he is a victim of the criminal justice system. Tomorrow, Blagdon faces a Parole Board panel in his latest bid to be freed.

A discretionary life sentence is the maximum penalty for arson, robbery, rape and manslaughter. Normally it is only given to very serious offenders, but a petty criminal who has not killed, injured, or endangered anyone can get life if a judge believes the defendant is disturbed or obsessive, and poses a threat to the public. On average a person convicted of murder serves about 13 years before being released.

Blagdon was jailed at a time when some judges gave "merciful" life sentences, which were supposed to help the offender by keeping them away from danger. "But in practice this means they rot in prison for years," says Ailsa Thomson, legal officer of Justice, the all-party human-rights and law-reform organisation. "There are people who have been forgotten by the system. They are often ineffectual people who have little idea how to look after their rights. It's a terribly unmerciful system whereby people are made ineffectual and inadequate by being in prison."

Judge Young, who sentenced Blagdon, later wrote a letter in 1978 to the then Home Secretary, Merlyn Rees, in which he said: "It seems to me a case where, in a just society, Blagdon should not be in prison at all, but in a secure place where he could be offered and given treatment."

Born in Guildford in 1951, David Blagdon was the youngest of three illegitimate children, whose mother was a certified patient at a mental hospital. After a few months he was fostered by Mr and Mrs Blagdon, who lived in a council house in the village of Kingston Lisle, near Wantage, Oxfordshire.

During his early years, David had emotional and speech problems. At the age of nine he was particularly affected by the death of a younger foster brother, who he later claimed to have smothered, even though he had died of bronchial pneumonia.

His mother was devastated by the death and took to her bed where she stayed for most of the next 15 years, spending her time watching TV. Blagdon recalls: "I don't know why she stayed there all the time, I think she blamed herself for the death of the child. I used to try and do things to shock her and make her get out of bed. I loved my parents, although they were strict and didn't allow me to bring friends to the house and we never went on holidays or trips out."

His mother died of cancer in 1977 and his father, who was a butler, died of a heart attack two days later after being transferred to a mental hospital. During his teenage years, David Blagdon spent several periods in Borstal, where he was described as aninadequate and damaged personality. Between 1965 and 1978 he appeared in court on 13 occasions for offences including assault, theft, burglary, and blackmail, for which he received several prison sentences.

He was also convicted on three counts of arson. The first, in 1974, saw him set fire to a van causing £12 of damage. In 1976 he ignited rubbish near some sheds causing them to be destroyed at a cost of £3,000. He also set fire to some rubbish bins.

He had attempted suicide on several occasions before the trial in 1978, taking overdoses or slashing his wrists and forearms. He had also been admitted to several psychiatric hospitals. Three medical reports carried out at the time of his final trial offered differing opinions about Blagdon's state of mind. Dr Spencer, a consultant psychiatrist, said he was suffering from a longstanding and severe disturbance of personality in a man of rather dull intelligence. He recommended that Blagdon be sent to a special secure hospital.

But two other medical experts concluded that Blagdon would not benefit from hospital treatment. They both gave the opinion that Blagdon had a severe personality disorder which was not susceptible to treatment. The judge asked for a further opinion but Blagdon refused to co-operate. At the time he wanted to be jailed. "I just wanted to get out of the way. I felt safe in prison," he says. But that was 16 years ago.

Now held in low-security Erlestoke Prison, near Devizes, Wiltshire, Blagdon speaks of his frustration at still being inside. He is surprisingly articulate - not the inadequate dullard described by medical experts 16 years ago. The only outward signs of his past life are dozens of scars criss-crossing his wrists and forearms.

"Every morning I wake up and think, I'm still in this sick hole. It can't be right that I've had to spend 16 years locked up. I came into prison with two lifers - one was a murderer the other manslaughter - they were both released four years ago. I don'tclassify myself as a criminal any more. The arson I did I now see as a cry for help - I wanted people to talk to, I wanted help. For the first few years being in jail I felt safe and secure, it was a bit like being at home."

Blagdon argues that he is a different man from the one who got into fights, set light to things and stole. While in jail, he has raised thousands of pounds for charity by making toys and is now trusted with matches and a lighter. Although he was very troublesome during his earlier years in jail, two confidential reports by prison staff in 1992 and 1994 both said they considered that he no longer posed a threat.

The law covering discretionary life terms was changed in the 1991 Criminal Justice Act and people are now only given such a sentence if they are considered a danger to the public for an indefinite period. Also under the 1991 Act, lifers must be told how long they have to serve before being considered for release, something which was previously kept a secret. Although there is no record of how many people have been incarcerated under the old "mercy" system, at least seven other people are serving life for starting fires that resulted in neither death nor injury.

Once an offender has served the minimum sentence, they go before the Parole Board's discretionary lifer panel, a process which is repeated every two years. The panel, made up of a judge, a psychiatrist and an independent member, has the power to recommend to the Home Secretary that the offender be released or transferred to a lower-security prison. Blagdon has already faced one panel, which refused to release him. He has a solicitor paid by legal aid to represent him at the hearing and is allowed to call witnesses.

Michael Mansfield QC, a leading civil rights lawyer, blames the prison and legal system for making it possible to jail minor offenders longer than killers. "Once a person enters jail, the reason they are there often gets forgotten and they just become part of the prison culture. They are often the most vulnerable and weakest people, unable to properly challenge a discretionary life sentence - more help should be provided to help them defend themselves."

Alun Michael, Labour's Home Affairs spokesperson, is calling for the setting up of a sentencing council to review current sentencing policy and practice. However, the Home Office argues that a discretionary life sentence is designed to ensure that dangerous people are not allowed back into the community. "There is an element of punishment involved but the courts have to decide whether the defendant is going to be a long-term threat," said a spokesman.

David Blagdon hopes that tomorrow, a system that has kept him in jail for more than a third of his life will help release him. He is asking to be sent to a 24-hour support hostel in Hull which has agreed to accept him. The Parole Board, however, are morelikely to recommend that he remains incarcerated - possibly at an open jail - for the foreseeable future.