who has died aged 91, was the driving force of the Northern Rock Building Society and a prominent figure in the economic development of the north-east.
Having begun his career with the Co-operative Permanent Building Society in London and Belfast, Osborn was recruited in 1949 to be general manager of the Northern Counties Permanent Building Society in Newcastle, where he remained for the rest of his life.
Founded in 1850, the Northern Counties was once one of 29 building societies in the city.
Amalgamations between societies began in earnest during the Second World War, and under Osborn’s forceful leadership in the 1950s the Northern Counties absorbed a number of smaller brethren, including the Crown, the Workington and the Elswick.
In due course negotiations commenced for a merger with the main local rival, the Rock Building Society, but the two had very different cultures – and both had formidable personalities at the helm. For eight years Osborn was unable to agree terms with the Rock’s chairman, the 3rd Viscount Ridley (father of the politician Nicholas Ridley).
Lord Ridley died in 1964, however, and the merger went ahead the following year, creating a society which had two-thirds of the mortgage business in the north-east and ranked 16th in Britain.
Osborn combined commercial vision with a belief in the community role of mutually-owned building societies.
A man of fierce integrity, he led by example without raising his voice and was a great encourager of younger colleagues. As chief executive of Northern Rock until 1978, he moved it to new headquarters at Gosforth and made further acquisitions of smaller societies. After stepping down from his executive role he remained on the board and was chairman from 1982 until 1987.
Fuller Mansfield Osborn was born on November 3 1915 at Clapton, east London, where his father worked for the Post Office.
He was educated at the Grocers’ Company School, Hackney. On leaving school he joined the Co-operative Permanent (now, after many amalgamations, the Nationwide) Building Society and later qualified as a chartered secretary.
During the Second World War Osborn served in the Royal Artillery with the Fourteenth Army in Burma, rising to the rank of major and commanding Indian soldiers, for whom he had a very high regard.
Though he rarely spoke of his war service, he liked to recall “strong men weeping” when Vera Lynn arrived to entertain the troops in the jungle. On demobilisation he returned to the Co-operative Permanent.
He was chairman of the Building Societies’ Association from 1969 to 1971, and became president of the Chartered Building Societies’ Institute in 1984 at a time of tumultuous change in the sector, as mortgage lending was deregulated and opened to competition from high street banks. An enthusiast for British co-operation in Europe, he was president of the European Federation of Building Societies.
He was also the prime mover in the north-east in the development of the Abbeyfield Society, which provides supported housing for older people, and was a member of the council of Newcastle University.
Osborn was appointed CBE in 1971. In 1974 he became the first High Sheriff, and a deputy lieutenant, of the newly-created county of Tyne and Wear. He was president of Northumberland County Cricket Club and also enjoyed beagling and studying history.
Fuller Osborn, who died on June 15 2007, married, in 1949, Maureen Auld; they had two daughters.