G4S’s success in this market shows that deportation, detention and border control have become big business. Boeing’s current contract to set up and operate a high-tech border surveillance system along the United States-Mexico border is worth $1.3 billion and involves nearly 100 subcontractors. The Florida-based Geo Group — one of G4S’s main competitors — manages 7,000 detention beds in the United States and, until recently, at the Guantánamo Bay detention center, where migrants intercepted in the Caribbean are transferred. N.G.O.s and international organizations profit, too. In 2010, the International Organization for Migration was paid $265 million to assist governments in returning migrants to their home countries, among other activities.

The migration control industry covers not only detention and deportations but also border control. Many airlines today employ former immigration officers or themselves contract security companies to perform the document, forgery and profiling checks required by destination states. In Israel, the West Bank checkpoints are gradually being transferred to private security companies.

Placing responsibility at lower levels may serve to insulate governments from lawsuits. In the Mubenga case, the three private security guards involved in the deportation were initially arrested. Following accusations from G4S employees that senior management had repeatedly ignored internal warnings about poor training and unsafe restraint techniques, charges against the company are now being considered. Yet none of these lawsuits are likely to address whether the U.K. Border Agency should face criminal liability for Mr. Mubenga’s death because of its decision to outsource deportations in the first place.

Even if governments want to re-establish state control over migration, it isn’t so easy. Political promises to renationalize immigration detention centers in Britain have so far remained unfulfilled despite repeated reports of abuse and mistreatment. And privatization, once pursued, is difficult to reverse.

The United States discovered this when, in the aftermath of 9/11, it was faced with the challenge of hiring 45,000 employees for the newly established Transportation Security Administration to recoup sovereign control over previously private airport security. And private contractors work to shape policy as well. When Arizona’s notorious SB 1070 immigration bill was passed, 30 out of 36 co-sponsors had received donations from private prison companies or their lobbyists.

Today, government outsourcing has given rise to an industry that encompasses nearly every aspect of migration management in countries across the globe. This shift comes at a price: It eliminates government accountability and runs roughshod over the rights of those subjected to private corporations’ control. And unless governments reassert control over what used to be a core sovereign function of the state, many more Jimmy Mubengas are likely to die.