Shouting to make herself heard above the power drills and bulldozers ripping up the central piazza in the picturesque hill town of Fiesole, Alta Macadam says: “This is a monstrosity.”

She points out the scaffolding propping up the medieval church of Santa Maria Primerana next to the town hall: “The church is falling down because of this vandalism. This must be stopped”.

From her home on the cypress-covered Fiesole hillside, Ms Macadam, author of the Blue guides to Florence, Rome, Tuscany and Umbria, has a stunning view of the valley below, with the Arno River and the dome of Florence Cathedral gleaming in the distance. She is a leader of the campaign to stop a “tidal wave of cement” from ruining the Tuscan landscape, with British residents of “Chiantishire” often in the forefront.

Tomorrow lawyers, architects and local people will gather in Fiesole to announce legal action to stop a series of unsightly housing and industrial developments that they accuse the left-wing council of putting through “in league with private developers”. The charge sheet, seen by The Times, accuses Fabio Incatasciato, the former communist mayor of Fiesole, and his officials of abuse of office.

The Fiesole campaign follows similar protests at the hilltop town of Monticchiello, in the Val D’Orcia near Pienza, which was declared a Unesco heritage site two years ago. Modern blocks of tourist flats are going up amid the olive groves below the town, in a development covering 7,000sq m. “This glorious corner of Tuscany will be blighted for ever,” Alberto Asor Rosa, a prominent conservationist, said.

Although “Red Tuscany” is a traditionally left-wing region, its authorities argue that they have to move with the times. “The paradox is that councils elected to defend the common good end up hand-in-glove with speculators, while private citizens band together to protect the public heritage” Ms Macadam says.

“The problem is that Tuscany needs jobs and economic investment,” says Matthew Spender, the sculptor and author of Within Tuscany, who has lived near Siena for 40 years. “Tuscans don’t want to be peasants, they want progress, understandably. But then you end up with these terrible suburbs and truly unspeakable holiday villages, like Tuscan versions of a holiday camp.”

At the medieval village of San Severo in the Val D’Elsa, near Siena, a new housing estate with an artificial lake is a “massive assault on the landscape”, according to Dario Conte, a local doctor. “Building speculation is a one-way street — once you have done it there is no way back.” Protest committees have also sprung up in neighbouring Umbria, where a shopping centre, hotel complex and tourist village of 200 flats is going up at the hilltop town of Trevi.

“The council and the developers say they want to encourage tourism, but they are destroying the landscape which attracts tourists in the first place” says Patricia Clough, a journalist and author, who lives in Trevi.

At the town hall in Fiesole, Mr Incatasciato defends the redevelopment of the main square, Piazza Mino da Fiesole, named after the Renaissance sculptor. “Until recently this was just an ugly car park,” he said as we looked down on the piazza, a dusty building site with an equestrian statue of Garibaldi marooned in the middle. “We have banned cars and are repaving the piazza with the original material. It will be a pedestrian space where old people can sit and children can play.”

It is true, Mr Incatasciato says, that the council has also sold off public land behind the town hall for €3.5 million (£2.5 million) to a developer who plans to erect a pharmaceutical research centre and a three-storey block of 28 flats, ostensibly to house the researchers.

“But the developer may not sell the flats for 20 years,” Mr Incatasciato said. Roman and Etruscan remains uncovered by the building work will be preserved in an archeological garden. “We have spent €400,000 on the excavations,” he said.

For Cosimo Marco Mazzoni, a law professor leading the Fiesole protests, this is meaningless. “First, the council can alter the deal. Second, what we will end up with is an ugly block of flats looming over the historic centre, with a two-storey private underground park which will destroy any remaining archaeological evidence. This a radical, invasive and disastrous project, a real eyesore”.

Mr Incatasciato says that the fuss will die down when the renovated piazza is unveiled in the summer. Giulia Maria Crespi, head of FAI, the Italian equivalent of the National Trust, said that speculative building in Tuscany was “like the plague. It is a fever in which everyone is caught up — even those who are supposed to protect the Italian landscape”.

A popular life in the sun

- 19,000 British citizens are registered as resident in Italy. Including seasonal residents, the figure is as high as 50,000, many living in Tuscany

- Tuscany was popular among artists and was the home of Robert Browning and Elizabeth Barrett Browning. Percy Shelley, pictured, drowned in 1822 in the Bay of Spezia

- Queen Victoria stayed in the hilltop hotel, The Villa Aurora, which was originally a theatre built by Sir W. B. Spence in 1860 to entertain local English aristocrats in Florence.

- Sir Harold Acton, the novelist, entertained the likes of D. H. Lawrence, Picasso, Churchill and Graham Greene at his family villa, La Pietra, a palace outside Florence.

- Lord Lambton, who died in December, went into exile at a villa near Siena after being forced to resign from government because of a sex scandal

Source: British Embassy, Times Archives, villaaurora.net, ahotelinitaly.com

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