We're not traitors, insist Greek's yes campaigners

Burgeoning citizens' group - with backing from academics and media magnates - warns of dangers of leaving European Union and euro

Thousands of flag-waving Greeks gathered in a summer thunderstorm outside the parliament in Athens on Tuesday to insist their country belonged in the European Union and warn that leaving would lead to calamity.

"It would take us so far backwards - a generation or more," said Ellie Douka, an employee of a non-profit company. "It'll be economic, social, cultural Armageddon," said Yiorgio Economos, a junior executive in a shipping firm. "This is just so dangerous. It's absolutely imperative that we stay in."

The situation is volatile. I can only hope that we are not going to commit national suicide

Related: IMF: austerity measures would still leave Greece with unsustainable debt