John Finucane

His son, solicitor John Finucane of Finucane Toner Solicitors, told The Irish News that the move showed the British government is “incapable of dealing with my father’s murder”.

A total of 5,974 “closure applications” were made by Whitehall departments to the British National Archives last year, up from 4,290 in 2016/17.

The younger Mr Finucane has consistently called for the UK government to hold an inquiry into his father’s 1989 murder amid allegations of British security forces colluding with loyalist paramilitaries.

Ex-Prime Minister David Cameron previously acknowledged “shocking levels of collusion” after the UK government published the results of a review conducted by Sir Desmond de Silva in 2012.

But campaigners have rejected that review as a “sham” that fell short of a full public inquiry.

Mr Finucane said: “The news that the British government has again used their power to prevent any light being shone on what they themselves have described as ‘one of the darkest chapters in their military history’ should come as no surprise to anyone who has followed our campaign.

“Given what is already in the public domain, given that the then PM David Cameron has admitted ‘shocking levels of state collusion’, which resulted in the murder of my father, it makes me wonder what more they have to hide.”