They have a beer ration of up to a litre a day, and wurst for dinner. Taleban or no Taleban, Germans take a little bit of home with them when they serve in trouble spots. Even their carefully sorted rubbish gets dumped in wheelie bins before being sent from Afghanistan to Germany for recycling.

Now Germany’s most senior officer has berated his troops for going soft. “We cannot guarantee soldiers that they will have an all-round feel-good experience,” said General Wolfgang Schneiderhan.

His outburst follows complaints made by German soldiers to the official ombudsman about their tours abroad. Some have grumbled about unsuitable sleeping bags for their Congo peace-keeping mission — “there is no reason why this issue should have come before Parliament,” said General Schneiderhan — while others moaned about the long hours, a lack of childcare for their families at home and poor medical care.

Army doctors say that they are on the brink of leaving because pay and conditions are so bad. So many have returned to civilian life that there is a shortage of medics in the field.

“We have to tell a professional soldier who complains about his third tour of overseas duty that he has to get a grip — this is his profession,” said General Schneiderhan.

“Perhaps the problem is down to the general tendency in society to delegate responsibility to someone else, or perhaps it is the stress associated with change,” he told several hundred army officers and politicians at an official reception.

It is a far cry from Germany’s old military traditions — the Prussian officers who helped to defeat Napoleon or the tactical flair of Rommel, the Desert Fox, but the troops’ reluctance will not come as a surprise to the country’s allies in combat zones such as Afghanistan, where German participation is limited by a host of caveats.

German Medevac helicopters have to be back at base by dusk. German Tornado aircraft are restricted to unarmed reconaissance. Der Spiegel magazine highlighted the case recently of a Taleban commander — nicknamed the Baghlan Bomber because of his role in blowing up a sugar factory in that northwestern province — who was cornered by the KSK German special service unit but allowed to escape; under the terms of engagement imposed by Parliament the KSK are not authorised to kill unless they are under attack.

Although the north of Afghanistan is not as quiet as it used to be — about 30 German soldiers have been killed since 2001 — other members of the ISAF force have voiced dissatisfaction about Germany’s contribution.

The reports of soldiers’ complaints made to parliament by Reinhold Robbe, the ombudsman, paint a picture of a force that is concentrating more on its own wellbeing than on the peace-keeping mission.

In 2007 German forces in Afghanistan consumed about 90,000 bottles of wine in addition to 1.7 million pints of beer; that figure has stayed constant. British and US bases by contrast have an alcohol ban.

The diet is heavy on carbohydrates, low on fruit and a higher proportion of soldiers are overweight than in the civilian population of Germany. Mr Robbe admitted that too many soldiers had a “passive lifestyle”. In short the soldiers are fat, they drink too much and spend a great deal of time moaning.

There are 3,500 German soldiers in Afghanistan. German troops also take part in missions in Kosovo, Bosnia and the Democratic Republic of Congo. For much of the postwar period Germans were constitutionally banned from serving on foreign missions.

Deployment still requires a parliamentary mandate and this gives complaining soldiers some clout. If they moan loud enough they can usually secure improvements but they continue to suffer equipment shortages, like their British counterparts.

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