First it was Warren Buffett announcing that he and his chums had been "coddled long enough by a billionaire-friendly Congress".

Then Liliane Bettencourt, France's richest woman, who was at the centre of a tax scandal last year, signed a letter along with 15 other billionaires begging to make a special contribution to the treasury to help drag France out of the financial crisis.

Even an Italian got in the action, with the boss of Ferrari saying that as he was rich, it was only "right" that he stump up more cash.

Now, as both France and Spain consider introducing a wealth tax, a group of 50 rich Germans have joined the "tax me harder" movement by renewing their open call to Angela Merkel to "stop the gap between rich and poor getting even bigger".

The German group, Vermögende für eine Vermögensabgabe (The Wealthy for a Capital Levy) is the latest manifestation of a feeling among some well-off individuals that the spare cash in their bank accounts might be able to ease, if not solve, the financial crises threatening to cripple their countries.

"None of us are in Buffett's or Bettencourt's league," said the founder, Dieter Lehmkuhl, a retired doctor with assets of €1.5m (£1.3m). "We're a broad church – teachers, doctors, entrepreneurs. Most of our wealth is inherited. But we have more money than we need."

The group's manifesto claims Germany could raise €100bn (£88.5bn) if the richest paid a 5% wealth tax for two years.

On Monday, Lehmkuhl said he was renewing his call, first issued two years ago, to Merkel's government to rethink its taxation policies. Currently the richest Germans are taxed a maximum of 42%. The previous chancellor, Gerhard Schröder, lowered the top tax rate from the 53% ceiling set by his predecessor, Helmut Kohl. Read full article in the Guardian...