McGonigal, Sir Ambrose Joseph (1917–79), judge, was born 22 November 1917 at 18 Herbert Street, Dublin, the second son of the three sons and four daughters of John McGonigal KC, county court judge for Co. Tyrone (1939–43), and Margaret Davoren, daughter of Richard Davoren, solicitor, of Friarsland, Roebuck, Co. Dublin. McGonigal was educated at Clongowes Wood College, Co. Kildare, where he was a first-class athlete, winning a Leinster schools rugby cap. He then spent what he later described as ‘two inglorious years studying arts’ at QUB (1936–7), before enrolling as a student at King's Inns in the autumn of 1938, intending to be called to the Irish bar. Ambrose's older brother, Richard McGonigal (qv), was a leading member of the Irish bar.
On the outbreak of the second world war in 1939 McGonigal enlisted in the British army and was commissioned into the Royal Ulster Rifles in 1940. He served with 12th commando (1943–4) and in the Aegean with the Special Boat Service (the naval counterpart of the Special Air Service) (1944–5). Awarded the MC in 1943, and a bar in 1944, he was mentioned in dispatches while serving with the Special Boat Service.
After demobilisation with the rank of major in 1946 McGonigal studied law as a bar student at QUB, and was called to the Northern Ireland bar in Michaelmas term 1948, aged thirty, having been exempted in view of his war service from the requirement to have a degree. Despite competition from contemporaries who had served in the war and were also called to the bar in its aftermath, he soon made his mark as a member of the junior bar, becoming a QC in 1956. As a silk he had a general common law practice, and in 1964 his standing as one of the leaders of the senior bar was confirmed by his appointment as senior crown prosecutor for Co. Down and election as a bencher of the Inn of Court of Northern Ireland. Although judicial appointments at all levels in Northern Ireland had hitherto been made predominantly from Unionist politicians or supporters, when it was decided to increase the complement of the Northern Ireland high court by two additional judges, McGonigal was the obvious candidate to fill one of the new posts – the other being the attorney general E. W. Jones QC MP; they were appointed on 3 March 1968.
A handsome but stern appearance, coupled with natural authority, meant that at times on the bench McGonigal conveyed an intimidating demeanour to counsel and witnesses alike. He was a man of decisive judgement and unimpeachable integrity, and any hint that the court was being misled or not told the full truth, or that counsel was not fully prepared, would result in an uncomfortable experience for the person concerned as the error was exposed in measured but icy terms. Nevertheless, any counsel who had been found wanting knew that on his next appearance before McGonigal he started with a clean slate.
The outbreak of political disturbances in the summer of 1969, followed by widespread terrorist violence, presented great challenges for the Northern Ireland judiciary. The creation of non-jury courts in 1973 meant that judges who now sat alone to try serious terrorist offences had a heavy burden to discharge in an environment of intense public interest and controversy while themselves at risk of attack, as the murders of a number of resident magistrates and county court judges demonstrated. McGonigal frequently presided in both jury and non-jury criminal cases, and was unflinching in discharging his duty. Although he generally handed down severe sentences, he could show considerable leniency on occasion, particularly where he considered that an impressionable young offender had been misled by older, more sinister figures.
On 28 May 1975 McGonigal was promoted to the court of appeal in Northern Ireland as a lord justice of appeal, and shortly afterwards was knighted and sworn of the privy council. As was the custom in Northern Ireland, after his appointment to the court of appeal he sat regularly at the first hearings of both civil and criminal cases. As the lord chief justice usually gave the leading judgment in the court of appeal, McGonigal had few opportunities to make a distinctive contribution to the development of the law, most of his judgments reported in the law reports being given at first instance. A sound and thorough lawyer, his judgments were rarely reversed on appeal.
Although a robust criminal judge, despite his wartime service in the British army McGonigal never hesitated to hold against the government where he felt the law required this. In 1971 he delivered a major reverse to the government in McElduff when he ordered the release of an internee who had not been validly detained. In 1976, in a forceful and closely reasoned dissent in the court of appeal in The attorney general for Northern Ireland's reference, he concluded that it would be unjustified for a soldier or policeman to fire at an unarmed man believed to be a card-carrying member of the Provisional IRA who was running away to avoid answering questions. While in 1977, in McCormick, he appeared to condone a degree of physical ill treatment falling short of torture or inhuman or degrading treatment to obtain admissions, in 1978, in Milne, he acquitted an unrepresented defendant who took no part in the proceedings, concluding that the admissions had not been shown to be voluntary where the defendant was interviewed for thirty-nine hours out of a total of seventy-two hours’ detention.
McGonigal was a member of many committees and public bodies in Northern Ireland, and served terms as a member of the senate of Queen's University and as a governor of St Mary's college of education. Keenly interested in the improvement of legal education, he made a significant contribution to the foundation of the Institute of Professional Legal Studies at QUB in 1977, at the time a unique institution providing for the common vocational training of barristers and solicitors.
McGonigal resided at Bishops Court House, Bishops Court, Co. Down, and died 22 September 1979, aged sixty-one, survived by his widow Patricia, the only daughter of Robert Taylor. They had two sons (Eoin, a senior counsel at the Irish bar, and David, a member of the English bar practising on the North East circuit) and two daughters. A fine drawing of McGonigal in judicial dress hangs in the judges’ corridor of the Royal Courts of Justice in Belfast.