The government has decided not to order a public inquiry into the 1989 murder of the Belfast solicitor Pat Finucane, despite calls from across the political spectrum for fresh scrutiny of one of the most notorious killings of the Troubles. Brandon Lewis, the Northern Ireland secretary, made the announcement in the House of Commons on Monday evening, delivering a devastating blow to a decades-long campaign for a new investigation into an attack that involved state collusion. Lewis acknowledged state collusion and apologised to the Finucane family for their suffering, but said there would be no inquiry pending a new police review of the murder. The decision was met with a barrage of condemnation. The Finucane family called it “astonishing, arrogant and cruel”. Michelle O’Neill, the deputy leader of Sinn Féin and Northern Ireland’s deputy first minister, accused Downing Street of protecting state-sanctioned murderers: “This is a cynical, duplicitous and shambolic political manoeuvre to deny accountability and facilitate impunity.” Amnesty International UK called it shameful: “This decision will add fuel to the fire of suspicion that there is and continues to be a sinister cover-up of the full extent of official involvement in this murder.” The decision to disregard pressure for an inquiry is the latest twist in a political and legal saga sparked by the brutal 12 February 1989 killing. Loyalist gunmen forced their way into the Finucane home and shot the lawyer, who was known for defending IRA paramilitaries, 14 times in front of his wife and three children. It later emerged that Brian Nelson, the Ulster Defence Association member who directed the organisation’s attacks, was an agent controlled by the British army’s Force Research Unit, a secret section of the Intelligence Corps. The murder ignited a political furore and led to the progressive exposure of other links between security forces and loyalist paramilitaries. Four Northern Ireland parties – Sinn Féin, the Social Democratic and Labour party, Alliance and the Greens – and the Irish government and 24 members of the US Congress had backed the campaign for an inquiry. Lewis, speaking to the Commons after briefing the family, said he recognised an appalling crime had been committed with state collusion. “It is plain that the levels of collusion in the Finucane case, made clear by previous investigations, are totally unacceptable.” However, the government had decided against a public inquiry because the Police Service of Northern Ireland planned to begin a review process into the murder and the police ombudsman was also going to examine the case, said Lewis. “I am not taking the possibility of a public inquiry off the table at this stage, but it is important we allow ongoing PSNI and police ombudsman processes to move forward,” he said. The government will reassess whether a public inquiry is necessary after the police review process and police ombudsman investigations, said Lewis. Downing Street remained committed to working with the Irish government, Northern Ireland parties and civic society to navigate the legacy of the Troubles and work towards a “more positive future”, he said. Tony Blair’s government promised a public inquiry in 2001 but consecutive governments reneged on the commitment. David Cameron’s administration commissioned a QC, Desmond de Silva, to review documentation about the killing. He concluded state agents were involved but that there was no “overarching state conspiracy”, a finding rejected by the Finucanes. The supreme court ruled last year that the original investigation into the murder was ineffective and failed to meet the standards required under human rights law, but stopped short of directing a public inquiry, calling it a matter for the government. The Finucane family, including the late solicitor’s son John, who is a Sinn Féin MP, condemned the secretary of state’s decision as an insult. “The proposal falls so far short of what it required in this case that it beggars belief,” the family said in a statement. “It makes a mockery of the decision by the UK supreme court … it is yet another insult added to a deep and lasting injury.” Labour’s shadow Northern Ireland secretary, Louise Haigh, asked if Northern Ireland citizens had to accept a lesser standard of justice. The Ulster Unionist party, however, welcomed the decision for not elevating Finucane in a “hierarchy of victims”. It challenged the Irish government to publish documents about the Irish state’s involvement in the Troubles.