The European Central Bank’s independence will be the centre of attention when its governing council meets on Thursday after a storm of criticism from Germany.

Even in normal times, ECB officials sometimes give the impression of operating behind enemy lines, due to some Germans’ misgivings about the eurozone’s Frankfurt-based central bank.

But this month has already seen a marked escalation. Wolfgang Schäuble, Germany’s finance minister, has launched an unprecedented attack on Mario Draghi, the ECB chief, and politicians from two other mainstream parties have piled in.

Since Thursday’s meeting is unlikely to unveil any fresh monetary stimulus, Mr Draghi may focus instead on defending policymakers against German criticism. The barbs have underlined the often-fraught relationship between the euro’s guardian and leaders in the eurozone’s largest economy.

The remarks matter because they challenge the ECB’s operational independence to set monetary policy to fulfil its mandate for price stability.

What have the ECB’s German critics said?

The strongest barbs have come from the rightwing of Angela Merkel’s ruling conservative bloc.

Hans-Peter Friedrich, a former interior minister and a member of the CSU, the Bavaria-based sister party of Ms Merkel’s Christian Democrats, told Bild newspaper on Monday that Mr Draghi’s easy-money approach had led to “a massive loss” of the central bank’s credibility.

He added that the next ECB president should be a German bound to the country’s tradition of monetary stability.

Bavarian finance minister Markus Söder and Hans-Peter Uhl, the CSU’s interior affairs spokesman, have made similar remarks.

Mr Schäuble said Mr Draghi’s ultra low-interest rate policies were “50 per cent” responsible for the rise of the rightwing Alternative for Germany party, which made big gains in regional polls last month, though he has since backed away from this claim.

Sigmar Gabriel, the leader of the centre-left SPD, said on Wednesday it was wrong to blame the ECB for Europe’s weak economy, blaming austerity policies instead. But he criticised the way the ECB had taken on the role of trying to stimulate growth, describing it as an “ersatz economy ministry”.

If the central bank remained the eurozone’s only economic actor, Mr Gabriel said, “the only growth we’ll see is in the popularity of rightwing populists in Europe”.

Why now?

On past occasions, German criticism of the central bank has clearly been provoked by ECB actions. When Mr Draghi launched his landmark quantitative easing programme last year, for example, relations with Ms Merkel became particularly fraught.

This time around, things may be rather different. Many analysts see the German attacks on the bank as a response not to the ECB’s latest round of stimulus in March, but to political problems within the country itself — notably an unprecedented wave of migrants.

While the ECB unleashed a fresh round of stimulus in March, the latest barbs seem more of a response to the German political situation.

Many of the 1m asylum seekers who have arrived in Germany over the past year have entered the country through Bavaria, the CSU’s traditional stronghold. The party fears voter defections to the AfD, which is also a fierce opponent of the euro and has made big gains in recent elections.

Are the comments representative of German public opinion?

The ECB certainly appears to be the focus of widespread resentment in Germany. Low interest rates have hurt German savers and smaller German banks that rely on interest income.

Low rates are also ramping up the pressure on German life insurers, which guarantee customers minimum returns.

As yields on government bonds — a key part of insurers’ investment portfolios — have fallen, it is becoming increasingly difficult for insurers to earn enough to meet past promises and meet regulatory capital requirements.

However, the debate in the German press and among the country’s economists is less one-sided. The conservative Frankfurter Allgemeine Zeitung recently featured a chart showing that real interest rates — which take inflation into account — were not particularly low by historical standards.

What does Angela Merkel think?

So far the German chancellor has kept out of the debate and evidently wants to stay out of it. But Ms Merkel could be forced to show her hand if her political position deteriorates ahead of national elections next year.

Has the ECB replied?

Not to date. The central bank wants to keep out of the debate as much as possible. However, Jens Weidmann, the president of Germany’s Bundesbank, has defended the ECB’s independence.