Panorama goes undercover in Britain's multimillion-pound trade in immigration visas and exposes the breath-taking frauds that allow bogus foreign students - some with little or no English - to remain in the UK.

Reporter Richard Watson unmasks the criminal immigration agents who - in return for cash - secure places at private colleges by arranging forged and fraudulent documents, including bank statements that are good enough to fool immigration officers.

The programme reveals how government-approved exams - designed to weed out those with inadequate English - are being routinely subverted with fake sitters taking spoken English exams for the bogus students and multiple choice tests where they're given all the answers.