A left-wing member of Plaid Cymru by the time he came down from Queen's College, Oxford, where he had read Modern History, even as a young man he was regularly consulted by Gwynfor Evans, the party's president, and subsequently by Dafydd Wigley, its long-serving MP for Caernarvon. He was also a member of the working party which advised Ron Davies, the former Secretary of State for Wales, in preparation for the Bill which paved the way for the National Assembly. He had never made a secret of his nationalist convictions, having stood twice as the Plaid Cymru candidate in Conwy at the General Elections of 1955 and 1959 and in Merthyr Tydfil in 1964.
Born in Dolgellau, Ioan Bowen Rees was educated at the town's grammar school, where his father was English master, and then at Bootham School in York. At Oxford, where he joined the Dafydd ap Gwilym Society, he resolved to brush up the Welsh language of which a wholly English education had nearly deprived him. He wrote with a vigour and authority which placed him among the political heavyweights of his generation. He had a profound interest in the writings of his compatriot Raymond Williams, who helped him to see himself as a Welsh European.
The country which inspired him most was Switzerland, in particular its cantonal form of government. He was a regular visitor to the Grisons, where he found not only a small language, Romansch, whose fortunes resembled those of Welsh, but also "a community of communities" whose model he sought to apply to Wales. For his seminal work Government by Community (1971), a study of Swiss democracy and an argument for saving local government in Britain from an overweening Whitehall, he was awarded the Haldane Medal by the Royal Institute of Public Administration; the book has an introduction by Max Beloff, who described it as "essential reading for public servants".
Ioan Bowen Rees began his career in 1956 as assistant solicitor with Lancashire County Council. Returning to Wales two years later, he worked as Prosecuting Solicitor for Cardiff City Council before moving to Pembrokeshire, where he became Deputy Clerk and, in 1973, County Secretary of the newly formed Dyfed County Council. In his professional capacity he played a prominent role in the public life of Wales: he advised the Association of County Councils and served as Chairman of the Society of Local Authority Chief Executives.
For him, "the local was the real" and he devoted his energies to strengthening local democracy in all its forms, often daring to argue against what he saw as the centralising policies of the Welsh Office. Much of what he set forth in his writing had for long been part of Plaid Cymru's decentralised socialism but it gained a wider currency, not least in some quarters of the Labour Party, and is now one of the several strands which make up the fabric of current political thinking in Wales.
Although he believed pessimism to be a healthier state of mind than an unfounded optimism, especially with regard to Welsh, he was a staunch friend of the language, which he spoke at home, and did much to establish it as the natural working medium of Gwynedd County Council, which serves a region that is still largely Welsh-speaking and on which Plaid Cymru has a majority of seats. But, no desiccated bureaucrat, he always saw things in human terms: "We bring up our children to speak Welsh, not for the sake of the language, but for the sake of our children."
At the heart of his concern for local democracy in Wales was his antipathy towards the numerous quangos which ruled Wales under the Thatcher government and of which the new Assembly is expected to make a bonfire. "There is always a danger of a small nation under the thumb of a large state becoming a nation of boot-lickers," he wrote. "The rise of the quango in Wales today is a threat to our self-respect." But he never failed to see Wales on a wider canvas: "The battle for Wales is a battle for all small nations, all small communities, all individuals in the age of genocide."
He published a number of pamphlets, notably The Welsh Political Tradition (1961) and Beyond National Parks (1995). His views found their first full expression in his contribution to Celtic Nationalism (1968), which he co-authored with Gwynfor Evans, Hugh MacDiarmid and Owen Dudley Edwards. More recently, his collection of essays Cymuned a Chenedl ("Community and Nation", 1993), represents his mature thinking about the nature of modern democracy and local autonomy, not only in the British but also in the European context. In this comparative work the Swiss cantons were again the source of his inspiration, but the federalism of Proudhon came to the fore, together with a staunch belief in a Europe of the Regions.
Ioan Bowen Rees made his home at Llanllechid, near Bethesda in Gwynedd, a former slate-quarrying district where he enjoyed the close communal ties and democratic spirit more commonly associated with the industrial valleys of south Wales. There he was elected president of the local rugby club, and indulged his passion for climbing; a few days before his death he had been on the summit of Moel Wnion (580 metres).
He published four collections of Welsh essays about the mountains of Snowdonia, the Alps, the Himalayas and the Andes, and compiled an anthology, The Mountains of Wales, which was published 1987 in a fine edition by the prestigious Gregynog Press and subsequently, in 1992, by the University of Wales Press. He was a founding member of the Welsh Mountaineering Club.
During retirement he explored two aspects of family history which gave him immense pleasure. His grandfather had been a missionary in Ndebeland, now Zimbabwe, where he was placed under the protection of King Lobengula during the 1890s Bantu uprisings. Having visited one of the schools established by his grandfather and made contact with the tribe which had shielded him, he was writing an account of this episode at the time of his death. Another ancestor was the cartographer John Evans of Waunfawr who, in 1793, set out to search for the Mandans, the reputed descendants of Prince Madoc, who according to legend had landed on American shores some 600 years earlier.
One of his sons, Gruffudd Rhys, is lead singer in the Welsh pop group Super Furry Animals.
Ioan Bowen Rees, solicitor, writer and local government officer: born Dolgelley, Merionethshire 13 January 1929; Secretary and Chief Executive, Gwynedd County Council 1974-91; married 1959 Margaret Wynn Meredith (two sons, one daughter); died Bangor, Gwynedd 4 May 1999.