Police academies have never quite recovered from the 1980s US comedy movie series, but the claims emerging from Berlin’s police training centre are no laughing matter.

The German capital is buzzing with allegations from whistleblowers that Arab clans in Berlin are working to plant family members as informants inside the police force.

The claims – and the police chief’s thin-skinned denials – have given rise to concern in the German capital. Almost a year after police botched their response to the Christmas market attack, the dismissive official attitude to criticism is now as much a part of the story as the original claims.

It all began with a WhatsApp recording in which an unnamed person claiming to be a police trainer complained of an unbearable atmosphere in some academy classes where up to 40 per cent trainees were of non-German origin.

The trainer claimed trainees refused to learn, were violent towards each other and concluded his tirade with the words: “They are not colleagues, they are the enemy. The enemy in our ranks.”

When the recording became public, further claims followed: that Arab mafia clans were trying to get family members into the force to report on investigations from the inside.

Slovenly appearance

Berlin police trainers complain in this week’s Der Spiegel how one entire class failed their arms training, and how many students had a slovenly appearance and showed lacked of respect for authority. A repeated concern: the rising number of Turkish and Arab recruits in the ranks.

“I’ve no idea how long this can go well until hardcore Erdogan fans meet Kurdish demonstrators,” said an unnamed source to Der Spiegel magazine.

Berlin police chief Klaus Kandt dismissed the infiltration allegations as “patently” false and unfounded. They put all police under a cloud of suspicion, he argued, in particular efforts to recruit from migrant communities.

Berlin’s interior minister Andreas Geisel said he was alarmed – not by the allegations but their “racist tone” seething with “xenophobic resentment”.

Opposition parties have called on the police to own up to problems in its ranks, whether xenophobic police officers or clan infiltration.

Critics see links between the latest problems and poor pay and conditions, low recruitment rates and a loosening of standards, such as in the fitness and German fluency tests.

Drugs and porn

“There are a lot of applicants who don’t even make it past the written test,” said Michael Haug, youth leader of the German police union.

One recent recruit was found to have been a drug dealer, another an amateur porn star who was reprimanded but allowed remain in training.

In June, scores of Berlin officers were sent home early from policing the G20 in Hamburg after a late-night drunken party including al-fresco sex and a striptease involving a bathrobe and a service revolver.

The common thread through it all, Berlin’s police union has warned, is the “absence of a culture that accepts criticism”.

And that, the union fears, has potentially left the Berlin police leadership blind to serious problems in the force, including what union leaders confirm are “concrete clues” of gang infiltration attempts.