THE widow of former Welsh Government minister Carl Sargeant has won the right to launch a High Court challenge against the terms of an inquiry into the circumstances surrounding his death.

Bernie Sargeant had asked for her family's lawyers to be able to cross-examine witnesses as part of the inquiry into the the actions of Carwyn Jones in the days immediately before and after her husband was sacked as communities and children secretary. He died on November 7 last year - just four days after losing his job.

And earlier today a judge in London granted Mrs Sargeant permission to launch a judicial review, ruling she had an "arguable case".

A full hearing is expected to take place in Cardiff on a date to be fixed.

Mrs Sargeant is challenging the legality of the operation of the inquiry, and has spoken publicly of her concerns that the investigation could become a "cover-up".

Her High Court action was launched to challenge "unlawful" decision-making in relation to the investigation's operational protocol, which will govern how it will proceed.

The decisions under fire include a decision to "bar the family's lawyers from being able to question witnesses", another "to allow the independent investigator to bar the family from hearings", and also a decision to "prevent oral evidence from being heard in public".

Nathalie Lieven QC, for Mrs Sargeant, argued before Mr Justice Supperstone that the way the terms of the investigation had been set amounted to a "flagrant breach of natural justice".

When news of the legal action was announced, Mrs Sargeant said: "We have a right to be able to hear and challenge the evidence.

"Please believe me, we are not trying to be obstructive, we just want to get to the truth and feel that we have a great deal to offer the inquiry. We don't want to be excluded."

She said: "All I want is to understand and process why my husband is no longer here. This whole thing just adds agony to heartbreak, but I owe it to Carl to get the full picture."

A spokesman for the first minister has said: "This is not, and was never intended to be, a public inquiry. Nor is it an investigation into the tragic death of Carl Sargeant."

He said: "The first minister established this investigation voluntarily, solely and specifically to give independent scrutiny of the actions and decisions which he took in relation to Carl Sargeant at the time of the ministerial reshuffle last November."

Mr Justice Supperstone heard argument on Mrs Sargeant's behalf following an earlier rejection of her case by another judge, who reviewed her application on paper.

He also heard from a QC on behalf of the first minister contesting the application.

Ms Lieven said the first minister had "personally and directly" been "controlling and approving" the terms of the operational protocol, "even though he is himself the subject of the investigation".

The "whole process has been fatally flawed", she argued.

Ms Lieven, who said the "evidence shows that the operational protocol has been set by the first minister", argued that the independence of the investigation "has been completely undermined by his interventions".

Cathryn McGahey QC, for the first minister, told the judge that there was nothing unlawful about his involvement, and argued that the "process is a fair one".

The first minister had the power, she said, to establish the investigation and to determine its terms.