In 2004 Greece dazzled the world by staging an Olympic Games in which the country’s ancient and modern culture was wonderfully displayed. Visitors to Athens were impressed by the way in which parts of the urban environment had palpably improved, defying the city’s image as a smog-ridden concrete jungle. In the Plaka district next to the Acropolis, where cars have been banished and the noisier night-clubs have been silenced, strollers could enjoy an agreeable mixture of classical remains, Byzantine churches and modern tavernas.

If some bits of the Athenian landscape have been preserved (in the nick of time and perhaps not for ever), that is in large measure thanks to a small but vigorous group of non-government organisations whose mission is to keep watch over a lumbering and fallible bureaucracy, and blow the whistle when some terrible aesthetic outrage is being committed. The most active NGO in this field is Elliniki Etaireia, the Hellenic Society for the Protection of the Environment and Cultural Heritage, founded by the businessman Costa Carras 35 years ago. As a vice-president of the conservation movement Europa Nostra, as a campaigner for a just solution of the Cyprus issue, and indeed as a thoughtful contributor to openDemocracy, Mr Carras is a respected figure far beyond his native Greece.

The Society has, inter alia, campaigned for the preservation of traditional architecture in Athens, including two fine inter-war buildings that were condemned because they blocked the view from the café of the new Acropolis museum. It opposed the fencing-off of Filopappou Hill, a precious green space next to the Acropolis. It is against a land-use law that would make it easier to build second homes on Greek islands. It has condemned the aerial spraying of olive-trees with dangerous chemicals. It opposes the diversion of the Acheloos river to irrigate water-guzzling cotton plantations; and it has campaigned for the preservation of the battlefield of Marathon as monument to the history of democracy. In all these efforts the Society has run up against some formidable and apparently well-connected opponents.

Such deeds, it would seem, are far too good to go unpunished. Just a few days before the Society was due to celebrate its 35th anniversary (a grandish public event, scheduled for April 15th), inspectors from the state archaeological service made a raid on the Society’s headquarters, located in Plaka. They accused the Society of illegally acquiring the antiquities on display at its premises. (In fact the archaeological service itself had not only authorized the Society’s possession of these objects, it had issued detailed instructions regarding their display, which the Society had scrupulously obeyed.) At the same time, police and archaeology service inspectors raided the nearby home of Mr Carras. They arrested him and detained him for three days - and accused him of illegally possessing antiquities as well as icons and other religious objects. Costa Carras, a devout Orthodox Christian, strongly denies these allegations and insists that all the objects in his home were legally acquired and indeed appropriately registered with the archaeological service.

“We are entitled to wonder which of the various criticisms we have made of the authorities has caused so much annoyance that certain people are resorting to denunciations, smear tactics” said a statement issued this week by the board of the Society. Having incarcerated the indefatigably public spirited Costa Carras for three days, the authorities must accept that this is a very fair question.