Mr Borjas admits to his organisation's lack of co-ordination with other drug-fighting outfits and the extreme lack of co-operation it gets from nervous Honduran citizens.

ECONOMIST: Honduras

But Mr Borjas also calculated how a rise in the number of migrants might have encouraged the creation of jobs, which reduced the impact on wages.

ECONOMIST: Of bedsheets and bison grass vodka

"An outflow of immigrants, or a reduction in the inflow, could actually lessen the recessionary pressures, " writes professor George Borjas, an expert on labor economics at Harvard University, in an e-mail.

FORBES: America's New Immigrant Capitals

George Borjas of Harvard University, who compared wages for different kinds of jobs where migrants most obviously compete with natives, estimated that immigration in America in the two decades to 2000 may have kept wages 3% lower than they would otherwise have been.

ECONOMIST: Of bedsheets and bison grass vodka