The scale of public opposition to Europe's largest onshore wind farm proposed for the Shetland mainland has been underlined after about 70 campaigners handed in a petition of more than 3600 signatures demanding the plans be scrapped.

A vociferous campaign against the 150-turbine, £800m development, led by the Sustainable Shetland Group, which has more than 600 members, culminated in the petition being handed into Lerwick Town Hall yesterday.

The signatures, representing almost 20% of Shetland's population over the age of 12, were given to Shetland Island Council convenor Sandy Cluness.

Viking Energy, which lodged the planning application in May, claims the wind farm would provide returns to the community's oil-funded Shetland Charitable Trust of more than £23m each year, and in total would generate upwards of £37m annually to benefit the 22,000 islanders.

But objectors believe the project endangers Shetland oil funds, and that project costs are underestimated while project income is grossly overestimated.

They say the turbines will be taller than Orkney's Old Man of Hoy and spread across almost 10,000 acres, to be seen from all over Shetland.

Viking Energy maintains the development will help Scotland meet its ambitious renewable energy targets. But, despite a community share of 45% in the project and the prospects of significant profits, a large proportion of islanders have now come out firmly against the proposal.

Mr Cluness, who two years ago signed the Viking Energy Partnership agreement with SSE, said he would take their concerns very seriously.

He said: "A large number of Shetlanders is opposed to the size of the project and I can understand that. I am anxious there should be the greatest debate possible and, if most Shetlanders are against it, of course we couldn't go ahead with it.

"This is a totally representative group coming from most areas of Shetland life. Their petition demonstrates that a fair percentage of the Shetland public is against a project of that size."

Rachel Smith, from Hillswick, said she feels very strongly about the subject: "It is too big for Shetland and they shouldn't build windmills on peatland. It will devastate the hills. I really feel good that I handed in the petition - I have done my bit for Shetland."

Sustainable Shetland said that 96% of those who signed the petition were locals. Chairman Billy Fox said islanders were very much in favour of renewable energy projects, but not on the industrialised scale proposed.

He said: "Sustainable Shetland is about exactly that, the sustainability of Shetland. We founded the group because we want to oppose the Viking Energy project. We feel it is too large for Shetland. We do not think its green credentials stack up because it is to be built on peat bog and blanket moor. We believe it would be at best carbon-neutral, but possibly even carbon-negative.

"What we really would like to see is projects developed that are smaller, fit for scale and would benefit the community more directly. Shetland could set a global example within the island microcosm of how we should be tackling climate change. We are not against wind energy. We want to see wind generation as part of measures such as energy conservation and other forms of renewables."

Mr Fox urged islanders to make their views known to local councillors, the planning department and the government's energy consent unit before the planning deadline of July 28.

Viking Energy was born of a partnership between Shetland Islands Council and Scottish and Southern Energy.