Immigration is a key issue in the US presidential election, with the Republican candidates trying to demonstrate their tough stance on undocumented immigrants.

But under the Obama administration, the detention and deportation of immigrants has reached an all-time high.

Every day, the US government detains more than 33,000 non-citizens at the cost of $5.5mn a day. That is a lot of money for the powerful private prison industry, which spends millions of dollars on lobbying and now operates nearly half of the country’s immigration detention centres.

Fault Lines travels to Texas and Florida to investigate the business of immigrant detention in the US and to find out how a handful of companies have managed to shape US immigration laws.