The Government is being urged to investigate how a convicted rapist was allowed to leave an open prison unsupervised before attacking a woman with a knife.

Neil Trennan, who was serving two life sentences for separate attacks on women, had absconded from HMP North Sea Camp when he broke into the 19-year-old's home and threatened her with a knife in July last year. 

The 61-year-old had been permitted to leave the Lincolnshire jail, where he was serving two life sentences, on unsupervised day release but did not return. 

Instead, the prisoner travelled to Sheffield and armed himself with a knife before entering the woman's home, having realised the door was unlocked.

She found Trennan in the spare bedroom, where he claimed to be 'lost', but quickly grabbed her and tried to push her onto the floor. 

As Trennan grabbed the knife from his pocket, the woman managed to knock it out his hand and escaped while he tried to retrieve it. She locked herself in the bathroom and quickly called for help.

The rapist quickly fled the scene and remained on the run from police for three days until he was snared in York on July 13. 

Just over a month since Trennan was handed another life sentence for the violent assault, shadow Justice Secretary Nick Timothy has urged David Lammy to conduct an investigation into the 'preventable attack'. 

In his letter, Mr Timothy accused the prison of failing in its 'first duty to protect the public' and demanded somebody 'must answer for the terrible decisions' that allowed the attack to take place. 

'An investigation is urgently needed to hold the right people to account and ensure this does not happen again,' he added. 

Mr Timothy also urged Mr Lammy to reveal who authorised Trennan's day release and on what basis, highlighting how the predator had 'continued to express violent sexual impulses as recently as 2024'. 

He demanded the Justice Secretary provide answers 'as a matter of urgency', adding that criminals such as Trennan are 'too dangerous to ever be released from prison'. 

The violent offender was handed his first life sentence in 1990 after breaking into the home of another woman in Sheffield, knocking her unconscious with a dumbbell and raping her. 

Trennan was also on day release in June 2002 when he committed another violent assault by attacking student with a brick in a female toilet in Norwich College.  

He was subsequently handed another life sentence for the attack, which Trennan claimed was not sexually motivated.

During his time in prison, Trennan admitted he was 'aroused by the violence' and enjoyed violent 'non-consenting' sex. In 2022, he also told a prison psychologist that he found committing offences 'more arousing than consensual one night stands'.

During his sentencing remarks earlier this year, Judge Jeremy Richardson also questioned how Trennan was moved to an open prison despite his previous offences and remarks in prison. 

He said it was an 'extremely surprising, and potentially wrong' decision for Trennan to be transferred to HMP North Sea Camp as he still posed an 'obvious risk of serious harm' and was 'massive danger towards women'. 

'I have been given no adequate explanation why this decision was made and this is something which the Lord Chancellor may wish to investigate,' the judge added. 

'It is astonishing to me that you were permitted to leave the prison in Lincolnshire on an unsupervised basis simply trusting that you would return. 

'Given the history and the obvious risks you posed – and you were expressing as late as 2023 and 2024 – it is astonishing you were subject to this liberal regimen.'

The Daily Mail has contacted the MoJ for comment. 

A spokesman for the department told the Sun: 'These were horrendous crimes and our heartfelt sympathies remain with all the victims affected. Neil Trennan has rightly received the full weight of the law for his actions.

'Protecting the public and victim safety is always our priority and transfers to open conditions are operational decisions put forward by the independent Parole Board, and after careful consideration, officials could find no clear grounds to reject this recommendation.

'We have not yet received the judge's sentencing remarks, however when we do, we will closely review the judge's comments to understand exactly what happened and to identify whether any procedures relating to this specific case need strengthening.'