Students from London Metropolitan University have staged their latest protest against the decision that could jeopardise their futures.
Five hundred are currently affected by the ban on the university recruiting from outside the European Union, after the UK Border Agency ruled it was not making proper checks on students.
They are now awaiting the outcome of a legal challenge against that ban.
Ronke Phillips reports.
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Paramedics were on standby outside the police cordon as armed officers stood by the property.
A team of researchers has taken samples from the ten busiest London Underground lines to work out which are the dirtiest.
The action comes on top of an emergency timetable which has seen hundreds of trains a day being axed.