Immigration minister Damian Green said London Metropolitan University was "very, very deficient" sponsor because more than a quarter of students sampled were studying there when they did not have permission to stay in the country.
A "significant proportion" of students did not have a good standard of English and there was no proof that half of those sampled were turning up to lectures, he added.
"Any one of those breaches would be serious. We found all three of those breaches at London Metropolitan.
"I'm not chucking anyone out, we have actually set up a task force to make sure genuine students can stay in the country" he said.
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The high of 35C was recorded on a Bakerloo line train between Piccadilly Circus and Oxford Circus at 2pm.
Weather forecasters say temperatures could reach 35C, beating the previous record of 34.6C in the scorching summer of 1976.
After years of political manoeuvring over the future expansion of Heathrow Airport, there has been an important development this lunchtime.