An urgent review was under way last night into how a rapist with a history of violence was able to abscond from a hostel in Yorkshire, remove his electronic tag and flee 250 miles to Somerset - despite being classed as one of the most dangerous offenders released from prison under licence.

A series of apparent failures to supervise Kelly Edney, which are exposed by The Observer today, are likely to provoke comparisons with a number of recent high-profile cases involving violent offenders who were out on licence and went on to commit further serious crimes.

Edney, 26, who was jailed for seven years for the rape of a 16-year-old girl in 1998, was under what the Home Office terms 'enhanced supervision'. He was supposed to be checked on every half an hour by staff at Box Tree Cottage hostel in Bradford, which is run by the Langley House Trust, a charity that works with offenders. His criminal history meant he was subject to a Multi-Agency Public Protection Arrangement order, which meant the hostel staff had been warned that he posed a serious risk.

In 2004 Edney was jailed for a further four years for making hoax phone calls from prison in which he threatened to blow up Heathrow airport and a number of railway stations. He also has convictions for arson, burglary and assault.

Yet last Tuesday night Edney broke off his electronic tag and made for Leeds railway station, where he caught a train to the West Country. He was picked up by police on Friday afternoon in Taunton, Somerset.

The Observer has established that Edney was not registered with Group 4 Securicor, the company charged with tagging him, as a high-risk offender, as he should have been under the protection arrangement. This meant the firm treated him as a less serious offender under home curfew.

Edney was captured on CCTV camera leaving the hostel at 9.47pm on Tuesday, having removed his tag. But because he was not flagged up in the system as a high risk, Securicor was not obliged to alert Langley House that the tag had been broken. 'The first thing we heard from Securicor was the next day when they came to pick up his tagging equipment,' said Cath Magee, director of the Trust. 'Edney was subject to regular reporting and there was no indication he would abscond.'

The alarming failure bears disturbing parallels with the case of Anthony Rice, a serial sex attacker who killed 40-year-old Naomi Bryant with a knife while out on licence from another Langley House Trust hostel, in Hampshire. Following the murder, the charity said its staff had been unaware that Rice was such a dangerous criminal. A subsequent inquiry into Bryant's murder found a series of deficiencies in Rice's supervision and communication between probation, police and hostel staff.

Last night the trust said it had launched a review in conjunction with local police and probation services.

A spokeswoman for Securicor said the company was confident it had followed procedures. 'As far as we are concerned, we've done everything correctly,' she said, adding: 'There will be a Home Office investigation.'

It is understood two staff members at the hostel failed to make two successive half-hour checks on Edney. They were disciplined on Wednesday, when the Home Office became aware that he had absconded. But Magee disputed the claim that hostel staff had failed to check on Edney and said the truth would emerge in the review.

Last night a Home Office spokesman confirmed Edney had been placed under an 'enhanced supervision' order following his release from custody on 4 September. 'When he absconded late on 25 September, his licence was revoked immediately and he was recalled to custody,' the spokesman said. 'An alert was put out for his arrest. He has now been arrested by Avon and Somerset Police.'

The failures surrounding Edney's supervision represent a setback for the Home Office as it battles to convince the public it is learning lessons about how to protect the public better.

Last month a joint inquiry by prison, probation and police officers, ordered by the government, described the management of high-risk offenders out on licence as 'patchy'. It found that nearly four out of 10 of the serious sexual and violent criminals among them are freed without proper risk assessments