The Government has said once again that it will not set up a public inquiry into the murder of a Welsh private investigator in 1987.
Daniel Morgan was 37 when he was murdered in 1987
Brecon and Radnorshire MP Roger Williams had used an adjournment debate in Westminster Hall on Tuesday to focus on the death of Daniel Morgan.
Mr Morgan, 37, originally from Llanfrechfa, Monmouthshire, was murdered 17 years ago in a pub car park, in Sydenham, south London, with an axe.
Home Office minister Caroline Flint said the government would not order a public inquiry.
"I do appreciate that the family of Daniel Morgan are frustrated, disappointed, angry, that no-one has been prosecuted for his murder and there are lingering concerns of police officer involvement in the killing," said the minister.
But she said that was not sufficient to embark on a public inquiry.
"The second reason for a decision to call an inquiry is that, after four investigations and a coroner's inquest, the Government does not consider there to be a realistic prospect of uncovering new evidence."
A request for a public inquiry into Mr Morgan's murder was first turned down by the Home Office last month.
Liberal Democrat MP Mr Williams is representing Mr Morgan's mother, Isobel Hulsmann, who lives in his constituency in Hay-on-Wye.
Speaking before the debate in Westminster Hall, Mr Williams said: "I am delighted that we have obtained this debate.
"At the centre of this tragedy is a gross insult to my constituent, Daniel's mother Mrs Isobel Hulsmann.
Mr Williams challenged the Government
"She has not only lost a son in the most brutal way, but has also been denied justice by the state through the failure of the Home Office to order a public inquiry into the circumstances of Daniel's murder.
"Allegations of police incompetence and corruption are perhaps secondary to the injustice, but are central to the Government's refusal to take this matter further.
"The only way now to resolve the issue is to order a full public judicial inquiry to call individuals to account and get to the truth.
After the minister refused a public inquiry, Mr Morgan's family, in mid Wales and London, announced it was setting up an action group.
That already has the support of MPs Chris Smith and Roger Williams and Lord Livsey of Talgarth.
Journalist Paul Foot has promised support, as has the Scottish writer Alasdair Gray.
Daniel Morgan was the co-owner of a firm called Southern Investigations, which employed off-duty police officers.
After the end of the most recent inquiry by the Metropolitan Police last September, the Crown Prosecution Service decided not to continue and the family lobbied for their reasons, before finally being given an explanation.
The six-page document released by the CPS in May revealed that an informant who named suspects targeted in the latest police inquiry had already withdrawn his statements.
Added to that, the report said there was a lack of scientific evidence - for example, blood or DNA - linking the murder to any suspect.
Also, no evidence was found around the crime scene to provide any clues about the identity of his attacker or attackers.