The Right Reverend Thomas McMahon (1936–2025)

26 November 2025

It is with great sadness that we share the news of the death of Hertford Honorary Fellow Thomas McMahon, Bishop Emeritus of the Roman Catholic Diocese of Brentwood, who died peacefully at his home in Stock on 24 November.

The Right Reverend Thomas McMahon was the Bishop of Brentwood, which covers Essex and five east London boroughs, for 34 years, becoming the longest-serving bishop in its history to date.

He was ordained to the priesthood in 1959 and served as chaplain of the University of Essex and parish priest in Westcliff-on-Sea, Colchester and Stock, before being appointed the sixth Bishop of Brentwood in 1980 at the age of 44: as the youngest Catholic bishop in Britain, he became known as ‘the Baby Bishop’. He made the unusual decision to continue living in Stock and to remain its parish priest, arguing that the location was more central to diocesan life.

Among his many achievements he will be remembered for the new cathedral at Brentwood. Designed by architect Quinlan Terry and dedicated by Cardinal Basil Hume in 1991, it was the first cathedral to be built in the classical style since Wren’s St Paul’s in London.

He felt a strong bond with Hertford since his identical twin brother, John, was Dean and Law Don at the college in the 1960s, and often came to preach in Chapel over the years. In 2004 he was elected as an Honorary Fellow.