Berlin has seen its fair share of squatters over the years, as befits a city that prides itself on its rebellious edge. But it is safe to say it has never seen anything quite like the occupation going on at Stille Strasse 10. It's not the building itself which is remarkable – an old community centre earmarked for redevelopment. It's the age of the inhabitants. The youngest is 67, the oldest 96. These are in all probability the oldest squatters in the world.

Dozen of pensioners took over the property in the east Berlin suburb of Pankow last month after the local council said the building they had used as a community centre for 15 years had to make way for real estate development.

The pebble-dashed house on a leafy street was once the house of Erich Mielke, despised head of the regime's hated secret police, the Stasi. The landlord has already changed the locks of the cellar, but the protesters say that as long as they are in the house it cannot be taken away from them, except by force.

"We're holding a very peaceful protest here," said Doris Syrbe, 72, the group's chairwoman and spokeswoman. "But we'll fight and not leave here until the council backs down, or until they carry us out in our coffins," said Helga Will, 84. Syrbe has made a pot of tea, tidied the kitchen and put flowers in a vase. "There's no reason why we can't keep going indefinitely, as long as our health holds out," she says, pointing out the numbers of supporters that have dropped by with food supplies, and noting that the kitchen facilities including the fridge and oven are in good order, "even though the kettle is in dire need of a descale".

Few squats are as orderly as this one. A rota determines who sleeps in the house and when, and who is responsible for washing up and cooking or brewing the coffee when the first squatters rise at 6am. There is an iron so that Heinz Schiller can ensure he keeps the sharp crease in his trousers. The 83-year old has lived in the suburb for decades, but has seen in recent years the district "occupied by the new rich and wessis", or west Germans. The streets around Stille Strasse, known as Majakowski Ring, once housed the East German elite, but have become a magnet for young well-to-do families whose freshly-plastered, energy-saving houses, manicured lawns, tennis courts and limousines now typify the area.

"We've lived a modest life for years and now find we're being squeezed out,and there's no one to protect us, as international property developers suddenly discover the value of Berlin," says Schiller.

He and his wife Helga recently lost their beloved allotment of 40 years to a residential building project. "Our hearts bled at that, so we don't want to lose anything else," he said.

Syrbe heads a guided tour through the house, past numerous camp beds and plastic sun loungers. Hers, with a yellow and white striped mattress, is in the corner of the front room, with a reading lamp she has brought from home. "It's moderately comfortable, but nothing like being in your own bed," she says. The wooden staircases and gables of the 1926 villa that was built for a piano maker hint at its past elegance.

In one room a group of pensioners is huddled round a table discussing strategy; upstairs, the bridge and chess groups are meeting. "They cannot be disturbed," Syrbe says. On the walls are notices about the different classes and clubs in which the pensioners can participate, including a canasta club, a singing group, and classes in English, mind training, gymnastics and self-help.

The pensioners' clubhouse, for which its 300 members pay membership of a euro each a month, became a refuge for many older east Germans who found themselves jobless soon after the reunification of Germany. Syrbe was 55 at the time, but told she was too old to find new work. "We gravitated towards Stille Strasse as a way to fill time, to keep busy and stop getting depressed," she said. "Unlike West Germans we didn't have fat pensions, golf club memberships, or holiday homes on Mallorca. We just had our clubhouse."

Visitors to the pensioners' squat have included grandchildren, great grandchildren, actors and politicians, including Gregor Gysi, a leading member of the socialist party, Die Linke, who pledged his support and said he would make the squatters' case one of his campaign issues. Jens-Holger Kirchner, deputy mayor of the Green party in Pankow, which has called on the pensioners to give up their fight, admits the local authority had not expected the group to put up such resistance. "Senior citizens occupying a house is something we've never seen before," he said.

Back in the kitchen, some sympathisers from a former 1960s squat in the west of the city have brought round a cake, iced with the pensioners' slogan Wir Bleiben Alle – We're All Staying. "When that's gone there are plenty of muffins," said Syrbe, swiftly wiping crumbs from the table.