Heads in the UK might complain about how difficult it is to fire bad staff - but their problems are nothing compared to Mexico. In the Central American country, not even being an alleged crime boss is enough to lead to disqualification from the profession.
Servando Gomez (pictured), nicknamed "La Tuta" (the Teacher), hasn't set foot in a classroom for over a decade, but like more than 100,000 other phantom teachers continues to be paid. Even being indicted for drug trafficking by a federal court in New York didn't get him sacked as a teacher, and despite millions being offered in reward for his capture, he remains on the payroll.
The education ministry admits that it is practically powerless in the business of hiring and firing teachers, given the political clout of the country's main teachers' union - the largest in Latin America.
Newly qualified teachers who come top of their class complain they cannot get teaching jobs because the union blocks their way. Poorly qualified teachers, on the other hand, can buy jobs belonging to retiring relatives.
The union makes deals with politicians to deliver votes in exchange for having its cronies placed in influential political posts, and many teachers are happy to be told who to vote for by their union masters. In return, the union protects teachers from being fired for almost any reason. Only teachers who have been convicted of a crime by a Mexican court can be sacked. Since Gomez hasn't been captured, he remains on the payroll.
Although it was last December when the newspaper El Universal reported that Gomez was continuing to receive a teacher's salary, it was not until August that Mexican lawmakers opened an investigation.
Gomez started teaching 15 years ago at a small rural primary school in his home town of Arteaga in the state of Michoacan. After a few years he left - while still being paid - and went into farming. Before long he is alleged to have started working for local drug smugglers.
He is accused of being a founding member of the notorious La Familia drug cartel. The group was known for its bizarre Christian morality, with none of its members allowed to consume drugs or take part in kidnappings.
The group claimed to protect the citizens of Michoacan by killing only rival gang members - some of whom were decapitated or burned alive. Under relentless pressure from the military, the leaders offered to disband if the government promised to "protect the people of Michoacan".
With the death or capture of La Familia's other leaders, it has been widely alleged that Gomez broke away and last year formed a splinter group called the Knights Templars. That group is also believed to have killed scores of rivals and attacked and killed dozens of police and officials.
According to US law enforcement agencies, the organisation is responsible for moving huge amounts of amphetamine and cocaine into the United States. But the man accused of being their ruthless leader continues to be paid as a teacher.