In preparation for his summit meeting with Harold Wilson shortly after becoming Taoiseach, Jack Lynch was briefed by various government Departments on matters which might arise. Peter Berry of the Department of Justice provided a one page aide memoire on what Berry called "the so called IRA".
Berry estimated that the number of the IRA "who would obey military orders" would be approximately 1,000. The number had "increased progressively from an estimated 650 in March 1962 when the organisation ordered a cessation of its campaign of violence".
Berry reported that "a certain amount of drilling with firearms" had taken place since the 1962 cessation; but "there was no more reason now than in the past four years to conclude that a campaign of violence is imminent or will commence within, say, the next 12 months."
However, "if the organisation were otherwise ready", he cited two excuses which might be used by the IRA to recommence violence: the Easter Rising commemoration ceremonies and what he termed "the Paisley sectarian riots".