LONDON (Web Desk) - A preacher who ‘despised Britain’ was leading a double life working within police counter-terrorism while defending extremist views and claiming non-Muslims would be ‘punished in hell’, it is claimed.

Abdullah al-Andalusi taught that ISIS was ‘no different to Western Armies’, reports The Sunday Telegraph, while working with the Muslim Debate Initiative, heavily backed by Saudi money.

He would preach at night, has an extensive profile online and even appeared on TV, and even claimed that the British Government wanted to destroy Islam, it’s been reported.

But by using a different name, Mouloud Farid, he was allowed to work in the heart of Britain’s policing, for Her Majesty’s Inspectorate of Constabulary which regulates all 44 forces in England.

The watchdog has admitted that it employed one of Britain’s most notorious extremists, and was only found out and sacked after appearing on television, the Daily Mail reported.

While working for the organisation, he was even promoted to a management rank, given him even higher access to sensitive information, including details on counter-terrorism units.

The inspectorate claimed he did not have access to classified material, but a source who worked with him told the Sunday Telegraph that this was not true.

The source said that al-Andalusi ‘despised Britain’ and talked about the right of oppressed people to take up arms against Britain.

However, he didn’t preach full time because he liked the stable income and pension plan.

MPs have now called for a full investigation into how he passed vetting checks and was appointed to his post.

In one inflammatory post, published on the 10th anniversary of September 11, he described the New York attack as 'the day a vicious world empire found a publicly acceptable excuse to bomb others, invade non-threatening nations, torture political dissidents and kill at least 300,000 innocent people.'

al-Andalusi is a prominent speaker on the extremist lecture circuit and has close links with terrorist lobby group Cage. The organisation caused outrage earlier this year when its leader Asim Qureshi defended ISIS executioner Jihadi John after he was unmasked as London-raised Mohammed Emwazi.

Mr Qureshi described him as 'extremely kind, extremely gentle and the most humble young person I ever knew'.

In a blog post published on June 30 last year, while discussing the creation of Islamic State, al-Andalusi said 'most Muslims would be jubilant at the claim of the return of the khilafah [caliphate]'.

He added the caliphate was a 'vital obligation upon Muslims that has been conspicuously missing for so long'.

Although he argued the group could not lay claim to a re-establishment of an Islamic caliphate, he condemned Western judgement of the group.

He stated: '[ISIS] are no different to Western armies, Western covert-backed groups and even some of the ‘founding fathers’ of Western nations - therefore they certainly have no basis to judge.

'[ISIS's] crime is being actually a good student of the West, right down to their corporate structure and organisation and ability to use social media.'

And in another article published on his website yesterday, al-Andalusi admitted his former role with HMIC, claiming working for a public watchdog corresponded with his beliefs as it helped his community.

He wrote he felt he had to resign because his former employers had noticed his views on TV, 'and took issue with my public criticism of government policies which lead to the arrest of Moazzam Begg'.

In the same article, he went on to defend Lutfur Rahman, the Muslim former mayor of Tower Hamlets, as having been 'demonised'.

This is despite the fact Rahman was found by a court as having run one of Britain's most corrupt political campaigns in recent memory after having silenced critics with accusations of racism and Islamophobia.

When contacted by The Sunday Telegraph, al-Andalusi said he was proud to have worked for a public watchdog. He claimed the organisation Cage was peaceful.

An HMIC spokesperson admitted he had passed security clearance checks but said he did not have access to 'secret material'.

The spokesperson stated: 'Mr Farid was investigated for gross misconduct by taking part in public activity that compromised his impartial service to government, thereby breaching the Civil Service Code.

'He was suspended immediately whilst investigations were ongoing. HMIC accepted Mr Farid’s resignation in July 2014.'