By the beginning of 1971 Catholics, who initially had welcomed soldiers with cups of tea and had welcomed the Hunt police reforms, were as alienated as they had ever been. Gaining recruits rapidly since the Lower Falls curfew of July 1970, the Provisional IRA had become a formidable guerrilla force. It had been at the request of Maj James Chichester-Clark, prime minister of Northern Ireland, that troops had been placed on active service in the streets of Derry and Belfast in August 1969. Now he desperately searched for remedies as the region became ever more convulsed by intercommunal rioting and ruthless guerrilla warfare.
Pressure on the government to adopt more draconian measures increased when, on February 6th, Gunner Robert Curtis was killed by machinegun fire, the first British soldier to die in Northern Ireland since the army had come "in aid of the civil power".
An outdated ratepayer franchise and electoral boundaries meticulously gerrymandered to unionist advantage had been potent causes of the civil rights explosion in 1968. O'Neill had promised wholesale reform in principle but only by means of bluster and threats in the privacy of the cabinet room in Downing Street had Harold Wilson been able to coerce Chichester-Clark and his colleagues into meaningful action.
Glumly reconciled to a complete overhaul of local government, Chichester-Clark and his cabinet hoped to postpone the pain for as long as possible, if only because so many rank-and-file party members regarded it as an unwarranted concession to Catholic agitators and terrorists.
Brushed off by Heath when he asked for stronger security measures and subjected to intense loyalist criticism, Chichester-Clark resigned on March 20th. As he explained, there was "no other way of bringing home to all concerned the realities of the present constitutional, political and security situation".
Three days later Brian Faulkner achieved his long-sought ambition by being elected prime minister. The most articulate of all Northern Ireland premiers, Faulkner had an air of professionalism which seemed to promise that the government could curb the escalating violence.
That hope was not realised. Catholics intensified their opposition to the Stormont regime. The death toll mounted remorselessly as once again the approach of the marching season raised political temperatures.
The cabinet records make no mention that the option of introducing internment was discussed at any meeting before August 9th, but it is quite clear from the minutes of August 17th that they were.
Internment had been discussed widely and openly as an option for bringing the region under control by many, including Tuzo, who had deep misgivings about its efficacy when he agreed to help impose it. Leading republican activists had taken care to evade the snatch squads when they moved out before dawn on August 9th. Terrible violence followed.
Discussion on the impact of internment was brief at the cabinet meeting the following day. Faulkner merely provided a brief review of the situation and said that the pattern of arrests "had not been unexpected". Harry West, the minister of agriculture, "urged the necessity of providing a better deterrent than rubber bullets".
The prime minister spent more time detailing plans to broaden the base of his government "to make progress in the achievement of greater consensus in conducting the business of government once the gunman had been eliminated". This clearly had been insisted on by Heath during talks at Downing Street the previous Thursday.
Internment was more fully discussed on August 17th. Dr Robert Simpson, the minister of community relations , said his "earlier reservations about the wisdom of internment were already known to the cabinet; these had not diminished over the past week and he was now particularly worried about the one-sided nature of the operation and about the divisive effect it would have on political opinion in Britain".
In fact internment was entirely one-sided. No attempt was made to arrest loyalist suspects: Basil Kelly, the attorney-general, said that "the police had been genuinely unable to furnish him with any information suggesting that a subversive organisation existed in the Protestant community".
Actually two Protestants were detained (John McGuffin and Ronnie Bunting), but both were no more than civil rights activists at the time. At a meeting later John Taylor "suggested that, in view of the criticism that the application of detention was one-sided, it might be made known that one or two Protestants were arrested for suspected IRA activities".
Faulkner was summoned to Chequers on August 19th to face Heath, the home secretary, Reginald Maudling, the foreign secretary, Sir Alec Douglas-Home, and the defence secretary, Lord Carrington.
The record of the meeting is by far the longest set of minutes in the 1971 Northern Ireland Cabinet Conclusions; it is evident, however, that Faulkner was concerned to bring home an account which would demonstrate to his unionist colleagues how well the Conservative government believed he was doing.
We know from other sources that this was an exceptionally difficult meeting in which it was made absolutely clear to Faulkner that, if the internment gamble failed, direct rule would be the inevitable outcome.
Having committed his government to backing internment, Heath was not about drop his support. He urged that the next "lift" should be carried out "at the earliest possible moment and that all available manpower resources be put into interrogation".
Faulkner replied that the Special Branch was "fully stretched at the moment carrying out interrogations and processing the material gained, which was better than expected". Maudling pointed out that the Police Federation had been assured that interrogators would not be made available from London. He added that "the reaction to internment had been more violent than anticipated".
Heath was clearly very anxious about "the propaganda being mounted against internment, the allegations of army brutality and so on". He and his ministers wanted "some sort of independent voice to reassure public opinion". They suggested "a high-powered two-man team consisting of, say, a distinguished doctor and a lawyer, to make an independent, but not an official inquiry as to how internment and other subsequent army operations had been carried out".
Heath was certain that the conditions in which internees would live "would become a major public preoccupation". He was not satisfied when Carrington assured him "that while the present conditions on the Maidstone were cramped, the accommodation being prepared was well above the standard of the average army camp".
He agreed with Douglas-Home that "some independent, international organisation" should be allowed to see the conditions of the internees. Faulkner was worried by newspaper reports that Heath intended to meet the Taoiseach, Jack Lynch. Heath responded that he could not very well refuse even though Lynch "was calling for the downfall of Stormont, possibly supporting civil disobedience campaigns, refusing to take effective action against Southern-based terrorists etc".
Faulkner did not agree with the foreign secretary that "it would be a pity if Mr Lynch were toppled, as he had personal qualities and influence which made him more desirable than any likely successor".
The opposition at Stormont had "precipitately and unwisely" withdrawn but the Conservative ministers were certain that "however culpable the opposition and other minority leaders had been, there was a need to wean them away from extreme elements and get them back into a more responsible position".
Maudling "had no very clear idea as to how this could be done, but he felt he must be involved". The government would be satisfied with "acceptable window-dressing" and agreed with Faulkner that "any moves to make special provision for minority interests . . . could only be within the framework of normal, majority-rule democracy."
Faulkner was cajoled into tripartite talks at Chequers with Lynch and Heath on September 27th and 28th. These conversations, he reported to his colleagues with satisfaction, "had served little useful purpose".
During the remaining months of the year ministers became increasingly frustrated by "the difficulties and delays in getting the UK government to accept courses of action advocated by the Northern Ireland government" to combat republican terrorism - "the social and economic fabric of the country required a much earlier end to the emergency than offered by the so-called long haul".
The mass arrests of August 9th had been followed by the most intense violence and dislocation to be experienced at any time during three decades of Troubles. The cabinet minutes do not reveal any premonition that the failure of internment would lead inexorably to the fall of Stormont and the imposition of direct rule.
Dr Jonathan Bardon is a historian and author of A History of Ulster