Image caption The Prison Service asked staff to remove the books from jails immediately

Five books regarded as "extremist" by the Prison Service remained in jails in England and Wales for seven months after a review called for their removal, the BBC has learnt.

Two of the authors are seen as having inspired jihadists in the Arab world.

Extremism academic Dr Chetan Bhatt said the presence of these books within prisons was "worrying".

The government said the texts had been identified as part of the Acheson review into extremism in prisons.

The BBC understands that Ian Acheson's inspection team first alerted the Ministry of Justice (MoJ) to the presence of the books in November 2015.

One or more of the texts had been found in chaplaincy rooms at nine of the 11 prisons visited by the review team.

Mr Acheson then submitted his report in March 2016 but publication of his findings has been successively delayed.

The BBC has learnt that the order to remove the books was only made on or after 20 June.

In evidence to the Commons Justice Committee on 13 July, Mr Acheson said his investigation had found "numerous examples" of books that were "extremist in nature in prison chaplaincies".

He said they contained "sometimes sectarian, homophobic and incendiary information that was freely available to vulnerable prisoners in many prisons with no obvious control over it".

'Free access'

In response to the BBC's findings, Mr Acheson said he was surprised that the MoJ had taken so long to remove these books from prisons.

"I made it clear to the Ministry of Justice last November that... my assumption was that urgent action will be taken to remove these materials", he said.

"Their free access to vulnerable and suggestible prisoners is an obvious security risk."

An email sent on or after 20 June to all prisons by the National Offender Management Service, which runs jails on behalf of the MoJ, described the books as "extremist literature".

It requested that prison staff implement the order "with immediate effect".

The banned titles are The Way of Jihad by Hassan Al-Banna; Milestones by Sayyid Qutb; The Lawful and Prohibited in Islam by Sheikh Yusuf al-Qaradawi; Towards Understanding Islam by Syed Abul Ala Maududi; and Fundamentals of Tauheed by Bilal Philips.

The BBC understands that the three texts written by Sheikh Yusuf al-Qaradawi, Syed Abul Ala Maududi and Bilal Philips were regarded as being in opposition to core British values.

Both The Way of Jihad and Milestones are regarded as having inspired jihadists in the Arab world.

Three of these texts were banned in Saudi Arabia in 2015.

'Targeted for removal'

Mr Al-Banna was the founder of the Muslim Brotherhood movement in Egypt while Mr Qutb, an Islamic theorist, was a leading member of the Egyptian Muslim Brotherhood in the 1950s and 1960s.

In the preface of The Way of Jihad, Mr Al-Banna writes: "Jihad is an obligation from Allah on every Muslim and cannot be ignored nor evaded… Those who can only find excuses, however, have been warned of extremely dreadful punishments."

Mr Al-Banna cites a large number of verses from the Koran to support his call for violent jihad, including from al-Anfaal, verse 60: "Against them make ready your strength to the utmost of your power, including steeds of war, to strike terror into [the hearts of] the enemies of Allah and your enemies."

He also quotes from al-Tawbah, verse 11: "Verily Allah has purchased of the believers their lives and their properties; for the price that [is] theirs shall be the Paradise. They fight in Allah's cause, so they kill [others] and are killed."

This verse of the Koran also forms part of the manual of the Tarbiyah programme, a Ministry of Justice-approved Islam course taught in prisons since 2011.

De-radicalisation expert Sheikh Musa Admani examined the Tarbiyah programme manual on behalf of BBC News earlier this year. He said the text risked "turning prisoners into jihadis" and should be withdrawn.

Media playback is unsupported on your device Media caption The BBC reported in June on the prison Islam course which a cleric warned 'could turn prisoners to violence'

Former Justice Secretary Michael Gove announced that the programme would be re-written following BBC News's report.

Dr Bhatt, Professor of Sociology at the London School of Economics, said the presence of the five withdrawn books within prisons up until June was "worrying".

"These texts are often standard fare among militant and authoritarian organisations and form the backdrop to their world view.

"The writings of Maududi, al-Banna, Qutb have been central to the growth of modern political Islam."

The Ministry of Justice declined to provide the total number of these books in circulation inside British prisons.

It said: "The justice secretary commissioned the first ever review of Islamist extremism in prisons.

"As part of this review, these texts were identified as containing extremist material and targeted for removal.

"The new justice secretary will now work closely with the Home Office and other agencies to tackle the important issue of Islamist extremism in prisons."