THE cause of a major fire which lit up the skies over a North-East city remained a mystery last night.

Fire investigators were yesterday unable to gain access to the partially-constructed student accommodation block in Newcastle, to start sifting through the remains.

The four-storey building, on the former Warner Bros cinema site, in the Manors area of the city, was destroyed and nearby buildings suffered partial damage.

But Northumbria University said its £103m City Campus East development should still open on schedule, by September, minus some nearby student flats.

The blaze centred on a privately-owned student residential development, leaving little damage to the university's nearby School of Design.

Only the "professional and highly-skilled" actions of the 20 fire crews, who attended the blaze late on Monday night, prevented worse damage. No one was injured.

Flames leapt 100ft into the air at the peak of the blaze, shortly after 10pm. A crane on site melted because of the heat.

The fire started in the partly-built accommodation block, which included a first-floor cafeteria, and damaged three nearby single-storey buildings.

Seven cars stored at nearby GTL Autos were destroyed, while two flat roofs and play equipment at a neighbouring school were damaged.

But the 50-plus firefighters prevented the school building and a church in the vicinity being damaged.

The new university building, to house the faculties of design, law and business, suffered scorch damage and glass panes were shattered.

A number of people in the closest homes, in Falconar Street, were evacuated for several hours.

Tyne and Wear Fire and Rescue Service's deputy chief fire officer, Iain Bathgate, who was at the scene, spoke highly of the actions of the crews involved. He said: "The fire was extremely severe and had the potential to spread much further than it did. I would like to praise all the crews, who had an extremely busy night in difficult circumstances.

"Their skill and dedication meant the fire was brought under control as quickly as possible and limited the extent of the damage."

Fire experts will not be able to get on site to start the painstaking investigation until council building control officials grant the all-clear.

Northumbria University said construction company Sir Robert McAlpine was inspecting the damage to the new School of Design.

A university spokeswoman added: "Fortunately, there were no injuries, and damage to the School of Design building was minimal.