A Tory cabinet minister has said that Britain’s increasingly secular society risks “pushing more young Muslims into the arms of Isis”.

Stephen Crabb, the Welsh secretary, used a speech to claim that a “hard-edged” secularism in Britain was partly to blame for “aiding and abetting” extremism, as mainstream religion is marginalised in public life.

Crabb is a committed Christian who voted against gay marriage and is one of at least two prominent members of the Conservative Christian Fellowship in the cabinet, alongside the education secretary, Nicky Morgan.

He made the intervention on Tuesday, the day after the commission on religion and belief in British public life proposed that schools should no longer face a legal requirement to provide daily acts of worship of a Christian character. It also suggested the teaching of religious belief should be overhauled to make it more relevant in a diverse and increasingly secular country.

Although extremism is not part of his usual brief, Crabb spoke about the issue as he gave the annual Wilberforce address for the Conservative Christian Fellowship.

The minister, who has been tipped as a possible outside candidate for the next Tory leadership race, said he thought freedom of religion was now under threat, citing the case of the advertising company that refused a Church of England cinema commercial promoting the Lord’s Prayer.

In the speech, he claimed the current mood meant “faith gets squeezed further into the margins of public life and religion becomes delegitimised through suspicion, fear or ridicule”. This could have implications for the fight against Islamic extremism, Crabb suggested.

“The answer to the seduction of Isil [Isis] is not a greater dose of secularism that delegitimises their faith in the public space,” he said. “I believe the marginalisation of religion in our national life risks pushing more young Muslims into the arms of Isil.”

He said it was not a good situation if a young Muslim growing up in east London, Cardiff or Luton only saw their faith being mentioned in mainstream British media in connection with death and violence.

“This is where hard-edged secularism ... actually serves to aid and abet the extremism we are all seeking to confront. Because if you push faith to the margins, then to the margins and into the shadows faith will be outworked,” he said.

Crabb also claimed it was difficult for politicians to speak about their faith and urged others to help “renormalise” religion in public life.

David Cameron has always described himself as a Christian but once also likened his faith to the patchy reception of Magic FM in the Chilterns. Cameron’s spokeswoman has described the refusal to show the Lord’s Prayer advert in cinemas as “ridiculous”.