Some staff at a prison in Thamesmead were unaware of how to identify and report suspected extremists, a shocking report has revealed.

Inspectors found that HMP Isis, a category C training facility within the parameters of Belmarsh prison, was working to prevent extremism and radicalisation.

There were regular "multi-disciplinary" meetings that identified individuals of concern because of possible radicalisation and allocated "clear actions", the report from HM Inspectorate of Prisons (HMIP) said.

It added: "Most staff we spoke to were aware of their responsibilities but, despite work to raise awareness of this issue, some staff remained unaware of how to identify and report suspected extremists and those at risk of radicalisation."

Chief Inspector Peter Clark branded the report “disappointing”, saying failure to deliver some basic challenges was “very poor”.

Earlier this year a government-ordered review concluded that Islamist extremism is a growing problem within prisons.

Plans are under way to create specialist units in the high security estate to remove extremist inmates from the general population.

At the time of the inspection in May, Isis prison held just over 600 men, nearly all of whom were under 30.

The inspection report said some inmates had as little as one hour a day out of their cells, while in a survey only 24 per cent of prisoners reported they could shower daily.

Chief Inspector Peter Clarke said: "As a training prison Isis was completely failing in its central purpose."

Levels of violence were said to be high while many wings were dirty and cells were poorly equipped.

However, security was well managed and health care provision was generally very good, HMIP added.

Mr Clarke said: "This is a disappointing report. Not enough progress had been made at Isis and the failure to attend to the delivery of some basic services, notwithstanding the evident challenges, was very poor."

Michael Spurr, chief executive of the National Offender Management Service, said: "Since this inspection the new governor has taken up post and made significant changes to the prison regime.

"More prisoners are now accessing education, training or work facilities, providing offenders with the opportunities they need to turn their backs on crime.

"Isis manages a complex young adult population and reducing violence amongst this group is challenging - but it is the governor's top priority and progress is being made.

"The governor and her staff will use the recommendations in this report to achieve further improvements over the coming months."