Plans for a new airport bringing cheap flights to Tuscany provoke furious opposition

Eight kilometres from the city of Siena, in the heart of Tuscany, is an airport. One of dozens in Italy that have never made any money, it consists of a 1,500m runway, a squat control tower and a terminal building out of a Tintin book. If you check the airport's website you will find that no flights are scheduled, either today or next week. One small, single-engine plane sits on the runway. Airport facilities consist of a pizzeria.

I visited the airport earlier this week. Two other things about it struck me. The air was incredibly sweet, heavy with the smell of sodden grass. And, apart from a faint clanking of crockery from the pizzeria, the silence on that winter night was total.

But it's not going to last. Last summer, the people of Siena woke up one day and opened their copies of La Repubblica to discover that their toy airport, built in the 1930s by Mussolini for the air force and of very little use to anyone since the end of the war, was on the threshold of dramatic change. The low-costs were coming! The no-frills revolution was heading Siena's way.

"Siena's airport takes flight" proclaimed the piece in the business section of the paper. "A radical transformation" is on the way, reported the article, "from fewer than 12,000 passengers to four million by 2020 with routes in the whole world. While the war of belltowers continues between Florence and Pisa, Siena is preparing for a great leap."

The aim of the operation, claimed the newspaper, was "the low-cost market and executive flights" because the company investing in the plan, a "dedicated transport and infrastructure equity fund" called Galaxy, "has good relations with RyanAir and easyJet, the two most important low cost companies at present, and knows that the other companies are very attracted."

The low-cost rivals, the report revealed, describe the little airport as "the best situation for an airport in Europe: a plain in which expansion is possible, and which in addition is beautiful."

Anybody who speaks up against low-cost airlines risks the charge of hypocrisy. We all use them and they are revolutionising our ideas about distance and accessibility and weekend breaks more dramatically than anything since the invention of the car. They are opening the skies to millions of people who have only ever travelled by train or coach.

Yet they are a menace, a dire and present threat. One aspect of that menace is to do with carbon emissions, global warming and all that: vitally important but very abstract. The other aspect could not be more concrete.

It pertains to the smell of sodden grass in the plain of Sovicille, outside Siena, the total silence there, the forest of stars shining above. Less visibly but no less tangibly, it pertains to the acquifers a few metres below the runway, the water table that provides Siena with 80 per cent of its drinking water. It pertains to the sheer survival of places of beauty and tranquillity, anywhere in western Europe.

Campaigners sprang up to oppose the airport last July. In what is unfortunately standard Italian practice these days, little had been said publicly about the its transformation before the media reports. And once the news broke, the local coverage was uniformly gung-ho. At last, Siena's "traditional isolation" was to end, said the reports. At last, the city would regain its rightful place in the Tuscan scheme of things – a place of which it was robbed about 700 years ago.

But within weeks, a disparate group of people from the city and the surrounding area – a tour guide, a lawyer, owners of bed and breakfast establishments, one or two foreigners – got together and formed a committee to oppose the airport's expansion. As the local press was uniformly backing the project they published a one-off magazine stating the case against. And when they held a demonstration in November, close to 3,000 people in this city of 60,000 turned out to join them.

Already they have had an impact. When asked when work on the airport's development would begin, the airport chairman, Enzo Viani, appointed a year ago, was unable to say with any precision. "We are awaiting the go-ahead from city hall," he said, "but they've been alarmed by this committee, and now everything is on hold".

The committee has clearly hit a nerve. Ever since the Black Death wiped out two thirds of the population in the 14th century and Florence imposed its rule, beautiful, unchanging Siena has been on the margins.

It had been one of the great cities of Europe but politically it melted away. And its marginality has continued to the present: it got none of the industrial development that transformed much of Florence, its rail link to both Florence and Rome remains partially single track, it was left out of the autostrada system. Siena has been Tuscany's Cinderella.

The airport, supporters claim, will reverse that historical injustice once and for all. But the critics say that the old fight for status is irrelevant now.

"The Siena countryside," says Cinzia Mariotti, a tour guide and one of the activists on the committee, "is the only countryside that still dominates in Tuscany. The isolation that led to Siena being cut out of the motorway network was negative for the city in the 60s and 70s but from the second half of the 80s and through the 90s it had a very positive effect: because we had preserved the beauty that other parts of the region had lost.

"All the images you see of the beauty of Tuscany are in fact images of the countryside around Siena: because we didn't have industrial development in the 60s and 70s, because we had no airport or motorways."

The committee insists that it is neither anti-development nor pro-isolation. "They insist on the necessity of the airport because the city is closed and does not have good communication links," Mr Mariotti goes on. "But the city's glaring problem is not the airport but the railway: the real priority is to complete the double track from Siena to Florence so you can get from one city to the other without stopping at every station. When we started protesting about the airport, they said we were Luddites and rabble-rousers.

"But we are not and we are not isolationists, we want an open city with a double-track railway line. At present, there are no fast trains and it takes 92 minutes to travel the 70km from Siena to Florence."

Tuscany already has two international airports, Florence and Pisa, 100km and one hour's driving time apart. Florence specialises in business traffic, Pisa has enjoyed dramatic growth in the past few years as a regional hub for low-cost carriers such as Ryan Air and easyJet. An international airport at Siena, 107km from Pisa and 88km from Florence, would make three.

The equity fund Galaxy was also the driving force behind the recent transformation of Exeter into an international airport. And the Exeter and Siena projects have other things in common.

According to John Stewart, of the campaigning group Airport Watch, Exeter is too close to Bristol to offer long-term viability as an airport. What both airports may offer, in the present overheated business climate surrounding the low-costs, is the chance to make quick money: to throw up some shed-like premises like those of low-cost hubs from Luton to Treviso, welcome in the RyanAir hordes and make money while air carriers remain untaxed and the price of oil does not become prohibitive.

Mr Viani, while admitting that the roaring growth of the low-costs is what has made the airport's expansion possible, rejected the idea that Siena's would be a cut-rate, utilitarian facility.

"As far as we are able," he said, "our intention is to build an airport of quality," he said.

The airport has just extended the useable length of its runway from 1,392m to 1,500m – opening the airport to planes with up to 80 passengers if not yet to the low-cost carriers' Boeings. He conceded that a further expansion of the runway was "theoretically possible" but added: "You know how difficult it is to get things done in Italy. It took from 1994 to 2001 to get permission to extend the runway to 1,500m. To change anything at all in this country you practically have to have the approval of the Pope ..."

By the end of March, however, Mr Viani expects to get the green light to proceed and then, unless someone high up in Siena has a dramatic change of heart, the bulldozers and cranes will begin to arrive on the plain of Sovicille and begin the transformation of the airport.

The committee fighting it calculates that to equip the airport for its new role – with new control tower, handling service buildings, police and customs facilities and so on will require 157,000 sq metres of concrete, equivalent to 23 football pitches. The industrialisation of the last unspoilt corner of Italy's most famous beauty spot will be under way.

My tour of Sociville, through rain and mist, concluded at Villa Cetinale, the house built in the 1670s to celebrate the election of Siena's own pope, Alessandro VII. From the mid-70s till his death last year, it was the home of the former Tory politician Lord Lambton. In drizzling rain, Cinzia Mariotti banged hopefully on the gate. Tate peer's son and heir, Ned, let us in and showed us around the spectacular garden, which rises at about 45 degrees to a hermitage that crowns the top of the hill.

Ned Lambton's son Fred did more than anyone to bring Siena's anti-airport campaign to the attention of people in Britain when – earlier this month – he took part in a demonstration outside the National Gallery in Trafalgar Square. The gallery is hosting an exhibition of Siena's Renaissance art.

We stood in the grassy amphiteatre that punctuates the vertiginous rise of Villa Cetinale's garden. "I'm opposed to the airport," he said, "and very proud of Fred for campaigning against it. He says he will do anything to stop it, including lying down in front of the bulldozers, though I think that might be leaving it too late."

"This is what we would lose," he added. We stood listening to the sound of Sienese silence. "And we'd never get it back."