Mr Cook was admitted to the role of solicitors in 1968 and became a prominent figure in the Alliance Party after the outbreak of the Troubles.

He became the first non-unionist Lord Mayor of Belfast in 1978 and, two years later, was elected deputy leader of the Alliance Party, a position he held until 1984. He was elected in 1982 to serve in the abortive Northern Ireland Assembly of the time.

Mr Cook later returned to the law, practising as a sole practitioner with Sheldon and Stewart Solicitors until his retirement in 2017.

The Law Society of Northern Ireland said it “extends its deepest condolences to his family, friends and former colleagues”.