AN INVESTIGATION into student numbers could thwart both Oxford universities’ hopes of moving into multi-million pound new campuses.

The city council probe will look at claims thousands more Students than previously admitted live in privately- rented homes in the city.

A dossier put together by East Oxford residents alleges far more students at the University of Oxford and Oxford Brookes University live in city homes than stated in their annual reports to the council.

Under planning rules, Oxford University will not be allowed to occupy its £500m Radcliffe Observatory Quarter and Oxford Brookes will not be able to open its £150m new Gipsy Lane campus if more than 3,000 students from each live outside university-provided accommodation.

If the numbers are breached, the universities will also be denied planning permission for new academic developments.

Oxford University says 2,688 full-time students live in city homes, while Brookes has vowed to reduce its numbers from 3,493 to below the 3,000 cap before it opens the new campus.

Sietske Boeles, of the Divinity Road Residents’ Association, has spent months filing Freedom of Information Act requests, investigating houses registered as student homes, and researching council tax exemptions granted to students in the belief the limits are routinely broken.

She added: “We believe there must be hundreds if not thousands more students in the city. We simply do not know. There are so many anomalies in the figures.”

In documents presented to the council, campaigners claim while 1,200 student rooms have been built over the last six years, the number of council tax exemptions on homes rented by students has gone up.

Since 2005, 900 more homes have become exempt because they are occupied by students.

And campaigners claim the electoral register shows more than one person lives in many of the 700 exempt homes listed as having a single student occupant.

At a planning appeal into Oriel College’s plans to build student flats in Bartlemas in May, the college said the university was “failing to comply” with its 3,000 target.

University bosses said the claim was based on out-of-date figures.

Council officers are poring over the residents’ evidence, and could ask universities for more data.

Deputy leader Ed Turner said: “We have very clear planning policies based on the number of students accommodated outside purpose-built accommodation for the two universities. Any question raised about either of these areas have to be taken seriously.”

He said if student numbers were above the cap, the planning rules would stop the universities occupying new buildings.

But he added: “I don’t want to jump to conclusions: residents have done some interesting research, and we will look at that.”

Students remained “hugely important” to Oxford’s economy, he said, but pressure on housing meant the council wanted more students housed in purpose-built blocks.

Both universities insist their figures are robust, and they are trying to house as many students as possible.

A spokesman for the University of Oxford said the way of counting student numbers had been agreed with the city council in the last year.

He added: “Any data issued by the university is done in good faith and in accordance with the university’s policies on data assurance, which is the subject of external audit.”

Oxford Brookes’ director of corporate affairs Anne Gwinnett said: “Address details are taken directly from our student records.

“We recognise the importance of the data and we continue to review our processes to assure and maintain their accuracy.”

The cap relates to full-time undergraduate and postgraduate students living away from home.