London: An undercover probe found widespread cheating and fraud within the UK`s student visa system which allows about 200,000 foreigners into the country annually, prompting the government to suspend the crucial English language tests.
A network of agents were found helping overseas students pass English language exams, obtain false documents and doctor their academic records by a BBC investigation.
In one case, an undercover reporter paid an immigration consultancy in west London 500 pounds for a "guaranteed pass" in an official English test staged as part of a requirement to prove applicants have the necessary language skills to gain a visa to study at a UK university.
Student visas are the biggest source of migration into the UK from outside the European Union, with Chinese and Indian students leading the charge. In 2012, almost 210,000 visas were issued to students from outside the continent.
The BBC`s Panorama programme said the tests are run by English Testing Service (ETS), one of the world`s biggest English language testing companies.
A Home Office statement said: "We have taken action and suspended the two colleges identified in the programme."
"Applications made by students in the UK using the English Testing Service or associated with the colleges or immigration advisors mentioned in the programme have been put on hold pending the outcome of those investigations. All further English language tests done through ETS in the UK have been suspended."
The programme filmed in secure exam centres where "fake sitters" answered questions or invigilators read out the answers for the candidates.
The "fake sitters" submitted their answers to a secure terminal, while the real candidates were called to be photographed as "proof" of taking the test.
"For too long many colleges, particularly private or further education colleges, have been selling visas and not education. It is time for them to face up to their responsibilities as purveyors of education and not abuse," UK home secretary Theresa May said.
"This type of abuse is not acceptable and as criminals, bogus colleges and economic migrants seek new ways to exploit the system we will continue to change our methods to clamp down on them," she said.
In a statement, ETS said it "maintains one of the most thorough test security protocols in the world and works closely with in-country representatives to monitor all aspects of test delivery".
"When testing on a global basis, no test provider can claim 100 per cent prevention or detection of fraudulent activity, but ETS does everything it can to detect and prevent rare instances of dishonest test administrators or test takers," it added.
Labour`s shadow home secretary Yvette Cooper said the investigation showed that the immigration system was failing.