CITY planners have refused to confirm whether it would be illegal for students to occupy the controversial Castle Mill development without the final sign-off.

Campaigners have warned Oxford University it could face “substantial” legal ramifications as it is still not considered to have fulfilled all the conditions needed to move tenants into the 312-room block in Roger Dudman Way.

It is believed it will continue to move students in, some in just 10 days’ time prompting concerns over future legal action.

Last night Oxford City Council refused to confirm what action, if any, would be taken if the university proceeds.

It comes after a key decision due to be made on Tuesday was postponed, leaving issues about contamination and a potential environmental impact assessment unresolved.

Toby Porter, from the Save Port Meadow group, said: “I would struggle to see how any organisation would be able to open a building for its residents without having dotted all the Is and crossed all the Ts, because if they did, they would be opening themselves up for substantial future liability.”

But John Goddard, the city councillor chosen as convenor of a panel investigating the council’s handling of the scheme, said his fears had been allayed over whether it was safe to move people in.

At the west area planning committee meeting on Tuesday, councillors were expected to sign off the scheme, with officers satisfied with the university’s measures to deal with concerns about contamination and landscaping.

But late legal advice resulted in the scheme being removed from the agenda.

City council spokesman Louisa Dean said the council had “obtained external legal advice” which recommended that a further technical assessment should be undertaken which would discover if a full environmental assessment was needed.

Asked if occupation of the rooms would be illegal, council spokesman Chris Lee said: “We don’t have anything to add about this at this stage.”

Helen Marshall, director of the Campaign for the Protection of Rural England Oxfordshire, which is mounting a legal challenge against the scheme, said: “The city council should call a halt to the development by issuing a discontinuance order and initiating a full environmental impact assessment.

“Until all of this is done, we think it is inappropriate that the buildings should be occupied.”

Oxford University spokesman Matt Pickles wouldn’t comment on the legal ramifications but said the authorities “understood the importance of deploying the much-needed purpose-built accommodation.”