SPRING is here: flowers are in bloom, birdsong fills the air, and the inboxes of employers are clogged with desperate pleas for summer internships. College students and graduates are well aware of the impact a plummy placement could have on their careers. With ever fewer entry-level jobs in many industries, internships have become a critical first step into employment. In America, three-quarters of students on a four-year university course will have toiled as an intern at least once before graduation. Up to half of these gimlet-eyed workers will have given their services free. Some may even have had to pay for the privilege of coming to work.

Unpaid internships seem to be an example of mutual utility: inexperienced youngsters learn something about a chosen field while employers get to farm out some menial work. The arrangement is consensual, and companies often use internships to test potential recruits. But the increasing popularity of these unpaid placements has caused some controversy lately. Nick Clegg, Britain's deputy prime minister, recently launched a crusade to ban them, arguing that they favour the wealthy and privileged. Others complain that uncompensated internships flout labour standards, exploit nascent workers and surely depress wages for everyone else. In America, they tend to be illegal at for-profit companies, according to guidelines set out in 1947. But the Department of Labour barely enforces such rules, in part because interns are often too afraid to file complaints.

Organisations in America save $2 billion a year by not paying interns a minimum wage, writes Ross Perlin in “Intern Nation”, a new book about the “highly competitive race to the bottom of the corporate ladder”. Perhaps one-third of all internships at for-profit companies are unpaid, and interns now often fill roles once held by full-time employees. “Young people and their parents are subsidising labour for Fortune 500 companies,” Mr Perlin comments.

To avoid legal complications, companies often encourage students to work in exchange for academic credits from their college. But such credits can cost hundreds or even thousands of dollars. Some colleges waive their fees or earn them by offering guidance and oversight. For many institutions, however, they are an easy source of revenue, more beneficial to themselves than their students.

Calls for new labour laws that reflect the growing prominence of internships have got nowhere. Instead, interns will have to look out for each other, for example by rating their experiences on websites such as InternshipRatings and Internocracy. At any rate, students may be buoyed by a rare bit of good news from the National Association of Colleges and Employers: employers intend to hire 19% more graduates this year than last. This should spare some from the drudgery of working without pay.