AN AL-QAEDA mastermind, attacked in a North-East prison with boiling oil and water, is back in prison following treatment at a local hospital for the "horrific assault" which has left him scarred for life.

An inmate of Frankland Prison, in Durham, believed to be senior al Qaeda operative Dhiren Barot, 35, spent several days in the Newcastle Royal Victoria Infirmary being treated for burns.

He is now back behind bars.

Northumbria Police, who deployed armed officers and an air support unit to the hospital during the prisoner's stay, are prevented from naming the prisoner who was treated, by the Ministry of Justice.

But The Northern Echo understands him to be Barot, 35, who was jailed for life in November 2006 for plotting to blow up a car park and flood the London Underground.

Barot's lawyer said a fellow inmate had thrown boiling water over the Indian-born terrorist's back, leading to a punch up, on Friday July 13.

Later, while Barot was nursing his wounds, another convict poured boiling oil over his head, the lawyer, Muddassar Arani said.

Northumbria Police confirmed today that a Category A prisoner, aged 35, was taken to the RVI on Monday for assessment, before being returned to prison.

He returned to the RVI on Tuesday to get treatment for burns, staying a number of days.

Durham Police and the Prison Service have launched an investigation into incident.

A Northumbria Police spokesperson said its security at the hospital was to protect patients, hospital staff, visitors, prison staff, the public and the prisoner.

The Northern Echo was aware of this operation, but agreed not to report it, in order to protect public safety.

Superintendent Jo Farrell, of Northumbria Police, said today the operation "passed without incident".

Supt Farrell, who led the security operation, said: "It's often the case that Northumbria Police is asked to assist the Prison Service with the security of prisoners needing medical treatment outside the prison. Security measures are always proportionate to the assessed level of risk, and maintaining public safety is paramount at all times."

Barot is one of the most high-profile prisoners convicted of terrorism offences in Britain since the attacks of September 11, 2001.

He plotted to blow up the London Underground, had detailed plans to explode limousines containing gas cylinders and considered using a radioactive bomb.

Sentencing him to serve at least 40 years behind bars, Mr Justice Butterfield said if successful his attack would have caused carnage on a "colossal and unprecedented scale".