Scotland's islands came together yesterday to launch a campaign for a powerful voice for some of Europe's most isolated and threatened communities.

Representatives from most of Scotland's 95 inhabited isles - from Unst in the north to Arran in the south - met on Mull to establish the Scottish Islands Federation, representing around 100,000 people.

One of its first actions, based on the largest survey of island opinion ever to be undertaken, will be to call for a government minister dedicated to promoting island interests and, if possible, a committee at Holyrood to monitor progress.

A primary concern fuelling the campaign is the long-running trend of island population decline, with many young people leaving for the mainland and ageing communities hovering on the brink of economic extinction.

In some cases, the situation has been exacerbated by rich incomers creating some of the UK's worst affordable-housing crises on islands such as Mull and Arran. The new federation, born out of the islands network, will form a steering group to oversee the transformation from a loose and dispersed organisation into a campaigning and lobbying body with a full-time secretariat to inform and advise government at local, Scottish, UK, and European levels.

At its inaugural meeting, the results of the survey of island opinion showed overwhelming support for the creation of such a body, and for ministerial and parliamentary recognition of the distinct needs of Scotland's islanders. Respondents also agreed, almost universally, that there should be a commitment at national and regional level for island ferry and air transport to be considered an extension of the national roads network. One of the architects of the move is Ian Gillies, a former councillor from Tiree.

He said last night: "I think there is probably an over-representation of politicians in Scotland at present, but the islands feel under-represented. What we would like to see is a cabinet secretary or a minister who would take responsibility for islands, not as a single remit, but as part of their portfolio to provide a one-stop shop. A committee of inquiry would be fantastic."

Camille Dressler, from Eigg, said the move was long overdue. She added: "We need to safeguard our cultural, economic, ecological, and environmental development for future generations. We can't do it on our own. We need to do it with other islands, to get more lobbying power."

Jim Mather, the minister for enterprise, energy and tourism, is to address the conference today, but has already indicated a lack of enthusiasm for new ministers. He said last night that the aim was for the whole of Scotland to enjoy sustainable growth "without new structures".

But Gordon Chalmers, the Mull-based councillor, responded: "Well if we can't get a minister, initially we would want at least a civil servant appointed as an islands officer."

Island problems are not unique to Scotland, as the European Small Islands Network stresses in a document, Meeting the Challenges of Small Islands, published earlier this year.

It said: "The challenges facing islanders are many: houses are expensive due to high market process, young people and families with children move to the mainland, and schools and shops close as populations decline, the provision of health and social care become difficult if not impossible, island businesses relocate, and transportation to and from the islands reduces."