A British imam who told children that martyrdom was better than academic success has been jailed for six-and-a-half years for supporting Islamic State.

Kamran Hussain, 40, was secretly recorded by an undercover officer giving a series of radical sermons over a period of four months last year.

After he was arrested, the defendant argued that the ability to discuss “difficult concepts in a challenging world” was an essential part of religion and claimed he was exercising his right to freedom of speech.

But following a trial at the Old Bailey, Hussain, from Tunstall, Staffordshire, was found guilty of two charges of supporting Isis and six of encouraging terrorism on dates between June and September last year.

Sentencing, Judge Rebecca Poulet QC said he had preached hatred and division. His encouragement of terrorism and support for Isis was calculated and intentional at a time of terrible terrorist incidents, she said.

Poulet added: “In my judgment these sermons represented serious and persistent although frequently indirect encouragement to acts of terrorism.”

Mitigating, Michael Ivers QC said his client was no Anjem Choudary, the high profile and influential preacher who was jailed for five-and-a-half years in 2016 for drumming up support for Isis. Before the trial, no one had even heard of Hussain, who preached at a small mosque, he said.

Hussain’s Friday lunchtime speeches at the charity-funded mosque in Tunstall high street, Stoke-on-Trent, were attended by about 40 worshippers, often including children as young as 10.

On 2 September last year Hussain talked about martyrdom to a congregation of nine children and 35 adults.

The prosecutor, Sarah Whitehouse QC, said: “Mr Hussain told his audience that martyrdom was the supreme success and was greater than any other success, such as school or college.”

He continued on the same theme on 16 September and criticised the Prevent programme, aimed at identifying and intervening when young people are at risk of radicalisation, jurors heard.

At a meeting on 19 August last year there were up to 15 children and 25 adults present as he gave a sermon about kuffar, or non-Muslims, the court heard.

Hussain was said to have blamed the British government for creating the English Defence League and funding them to insult Muslims and put them down.

He also claimed the far-right group Britain First was a “government-backed project”, jurors heard.

In all, the undercover officer known as Qasim attended 17 sermons, 10 of which “strayed beyond the mainstream moderate Islamic thought”, Whitehouse said.

On 24 June last year Hussain referred to Isis in his sermon as “a small fledgling state who is standing in the face of a pompous and arrogant army”.

On that occasion he called on the congregation of 10 men to pray for their victory and for their oppressors to be “annihilated”.

The court was told Hussain had one previous conviction, in 2008, for perverting the course of justice, for which he was sentenced to 14 months in jail.

Pakistan-born Hussain had been an imam at the mosque for six years. The court heard there was no evidence anyone had in fact been encouraged to commit terrorism as a result of his sermons. He made no reaction as he was sent down.

DDCS Matt Ward, of West Midlands counter-terrorism unit, said: “Hussain was espousing hatred and violence as well as clearly demonstrating his support for Daesh [Isis] through the content in his sermons. During this investigation we used covert methods to record these sermons and present it as evidence during the trial. We will continue to use every lawful technique and power available to us to tackle terrorism.”

Wayne Jones, Ch Supt for local policing with the Staffordshire force, said: “The actions of this man, who was supporting radical and violent extremist behaviour, have no place in our society, and we will continue to be relentless in our efforts to keep you safe by taking appropriate action whenever we are provided with information about any form of extremism.”