Personal life
Montague Browne married twice. His first marriage, in 1950 (dissolved 1970), took place in Cheltenham and was to Noel "Nonie" Arnold-Wallinger. He had one daughter from his first marriage. He married secondly, towards the end of 1970 in Wandsworth, Shelagh Macklin (née Mulligan), the former wife of racing driver Lance Macklin.
While working for Churchill, Montague Browne had an affair with Jane Gillian Portal (1929−2023), one of Churchill's personal secretaries, from 1949 until her marriage to Gavin Welby on 4 April 1955 (Jane Portal later married Charles Williams). In 2016, DNA tests showed he was the biological father of her son, Justin Welby, the former Archbishop of Canterbury, who was born on 6 January 1956.
Montague Browne died at his home in Bucklebury, West Berkshire, on 1 April 2013. A memorial service was held on 25 June 2013 at St Clement Danes Church on the Strand, London.