Cardiff University has installed metal cages by warm air vents on campus to stop homeless people sleeping by them.

Students say they are “disgusted” by the move but the university claims the grilles, outside a chemistry building, are necessary for health and safety.

Student Lewis Hopkins, who blogged about the cages after spotting them on his daily walk to university, said he was “sickened”.

“The homeless people are never there in the day, it’s only overnight,” he told The Independent.

“They never caused any trouble, never littered nor gathered in groups,” he added.

“They were just content with finding a warm place to sleep at night.”

A Cardiff University spokesperson stressed that the grilles were installed outside the Sir Martin Evans building “in the interests of health and safety”, not to deter homeless people.

“These vents are considered safe in normal use due to the type of flue dilution system being used but there could potentially be an increased risk if people are sleeping right next to the grilles for very long periods.”

He said the university had been working with security staff on the issue and said the cages would reduce risks to anyone sleeping nearby.

The controversy comes after a Tesco in London provoked outrage with “anti-homeless spikes” outside a shop, following a similar move outside a flat development.