With increased competition and pressure on funding, many UK universities have looked to the lucrative overseas student market.
This is because overseas, non-EU, students pay higher fees than home students.
In 2010-11, there were a total of 48,580 overseas undergraduates and 79,805 overseas postgraduates.
With regard to the key UK undergraduate population, it represents about 11% of the total.
But this translates to 32% of universities’ fee income.
Overall they contribute an estimated £5bn a year to the economy in terms of fees and wider spending.
Universities UK says this could increase to £16.9bn by 2025.
But it has warned that moves to tighten visa rules will hit the ability of UK universities to recruit foreign students.
The NUS and academics union, UCU, also fear that taking such a tough stance with London Metropolitan will send a damaging message to bona fide potential students eyeing UK universities from abroad.
However, the UKBA says London Metropolitan has failed to carry out basic procedures tracking the status and activities of its overseas students.