Forty-one prisoners have escaped from jails or from the supervision of prison staff, and another 319 either walked out of open jails or did not return from day trips.

In the first five months of this year four prisoners managed to escape from jail and 34 have absconded.

The most high-profile of these individuals is Bolivian drug dealer Juan Carlos Alba, who managed to give two prison officers the slip while doing community work in Ballymun. He has not been found.

In 2006, nine prisoners fled from custody and another 79 absconded.

The vast majority of these have either surrendered or been located and sent back to prison.

In 2005 there were nine escapes.

Three of these occurred at the D�chas Centre women's prison. The other six inmates escaped from the custody of prison officers while outside their jails.

Most of these incidents happened while the prisoners were attending court or receiving medical treatment.

Upwards of a dozen other escape attempts were thwarted by staff.

Eighty-one prisoners absconded from custody, with the majority not going back to open prisons after work details or time off. Shelton Abbey open prison saw 32 prisoners abscond while 32 inmates walked out of Loughan House.

Fifty of the absconded prisoners had either returned or been located by the end of 2005. In 2005, 10,688 inmates were admitted to prison, meaning that 0.74% of prisoners either escaped or absconded.

Seven inmates escaped from the custody of prison officers in 2004 but there were no actual escapes from jails.

Sixty-six prisoners absconded from custody. Thirty prisoners absconded from Loughan House open prison while 29 left Shelton Abbey.

With 10,657 inmates being committed to jail in 2004, the number of escapes stood at 0.68% of all committals.

In 2003 two inmates managed to escape from Limerick prison but were recaptured a short time later. Another 10 prisoners managed to escape while in the custody of prison staff either on the way to court or to receive medical treatment.

One inmate escaped on an escorted family visit. All but one of these escaped prisoners were recaptured after short periods and sent back to jail.

Loughan House and Shelton Abbey were the scenes of by far the biggest number of escapes. Out of 70 escapes, 33 were from Loughan House and 31 from Shelton Abbey. That year, 11,775 inmates went through the country's prison institutions with escapes happening in 0.70% of cases.

Escaping or absconding is classed as a serious breach of discipline and incurs severe internal penalties such as a loss of remission or increase in sentence.

Garda� can also bring criminal charges if there are third parties involved in escapes or if innocent people are injured.

Prison sources say that while it is never desirable that any inmate goes missing, the vast majority of incidents occur at open prisons where the regime is relaxed and most prisoners are preparing for release or are petty offenders. Irish escape rates are low internationally.

Garda� are still searching for Juan Carlos Alba who has now been missing for 20 days. The 42-year-old is nicknamed 'the chemist' and was sentenced to eight years in July 2004 for his role in an international cocaine-trafficking operation.

He used a chemical process to extract cocaine from a liquid and was found with Euro255,000 worth of cocaine in a makeshift laboratory in Kilkenny when it was raided by garda�.

Alba had been on a work party for 10 weeks in Ballymun before he fled. He had been renovating a house for a local arts centre. Garda� believe he is still in the country.

Mountjoy governor John Lonergan personally approved his release into the party even though he was a convicted drug dealer. The opposition has branded his escape "a total farce".

Alba is not the only high-profile escapee in recent years. In December 2004, 27-year-old Ian Stewart from Tallaght fled while he was visiting his sick mother in a hospice at Harold's Cross.

Strict orders had been given to his three-man escort that he should remain handcuffed at all times. He was uncuffed, however, and escaped through a window while an accomplice waited nearby with a car.

Stewart had been serving 10 years for armed robbery and assault and garda� described him as dangerous. It was several months before he was found.

In February, three prisoners escaped from custody after breaking out of a custody cell in Anglesea Street courthouse when they rushed at prison officers. They were arrested that same day.

In January 2001, a prisoner was being transferred by private minibus from Dublin district court to Cork when he produced a syringe and held it against a prison officer, demanding to be released. Patrick Brassil, 24, was serving 10 years for armed robbery.

Just a week later, Adrian Duke, 29, from Farranree, Cork city, escaped after an armed gang intercepted the minibus in which he was travelling from Waterford to Cork. The gang of three smashed the windows and demanded his release.

Duke did manage to get away but was detained after a few days. He was subsequently convicted of armed robbery, as were several others.