Lindsay Shaw spoke to Michael and Lisa Gungor of the Denver-based collective GUNGOR

Lisa and Michael Gungor

Whether they're leaving the safety of a Christian label and US mega-church, switching styles unannounced from moment to moment, or digging deep into theology and human experience, Denver-based Gungor are breaking all the unspoken rules of contemporary Christian music. Yet their creativity and authenticity enthralled UK audiences on their first two visits. After dazzling the Mainstage crowd at Greenbelt 2011, The Big Church Day Out earlier this summer was only the Denver band's second visit to the UK. This time, on an overcast, Jubilee weekend they rapidly won new fans, firstly by their musicality (all manner of guitar styles, classical cello, haunting vocals) and dextrous genre-hopping (from Sufjan Stevens to Muse).

But, ultimately, Gungor beguiled with beautiful and powerful songwriting and lyrics that articulate both God's longing to sign up flawed human beings to his great new creation project and our yearning to become new. "It's the future Heaven crashing into the present earth," commented Michael. God's new creation is a theme which saturates Gungor's latest albums, 'Beautiful Things' (2010) and 'Ghosts Upon The Earth' (2011).

Explained Michael, "During the time of 'Beautiful Things' I was reading a lot of N T Wright and different theologians who have opened up my view of God and the world and his story. I come from an evangelical background where it tends towards a far more individualistic story; it's much more 'me and how I go to Heaven'. Having the story opened up, realising this is GOD's story, he's the creator of all things and we're invited into this process of recreating that started with the empty tomb - that has been very inspiring."

While his first album (as The Michael Gungor Band) showed welcome tendencies to abscond from the dominant rock worship genre, this light-bulb moment drove him further. "It's very easy as a worship leader to listen to other voices," he confided. "It felt almost righteous because I was doing it to serve the Church. Then I thought maybe to best serve them I should listen to the voice I was created to have. Ironically," he laughed, "people seem to like it more than anything we've ever done."

While we're speaking of new creations, what is this 'liturgical post-rock' genre Gungor have invented? Michael said he coined the term while blogging, partly as a reaction against the term 'Christian music'. Explained Michael, "The idea of a division between sacred and secular - I never understood that. Musically, we're post-rock. The liturgical element is that there are parts of the set where we're intentionally trying to have people singing to open themselves to God and have intentional prayer." Lisa, keeping the conversation grounded, chipped in: "If you create your own genre, you [can] be the best at it!"

The liturgical element in Gungor's work is noticeable in lots of ways. From the aggregation's eschewing of trite, clichéd lyrics in favour of poetry, in themes that run the gamut of human and biblical emotions (from lament to praise) and in their borrowing of words and ideas from Christian giants as varied as Saint Francis, C S Lewis and Mother Teresa. Commented Michael, "There's room for pouring out your heart. There's a lot of that in the Psalms. Singing a lament is theologically accurate." It may not always be "factually accurate" he said, "but it's what the Psalmist FEELS. We've got a song based on the lamentations of Mother Teresa which says things which are really intense: 'The torture and pain, I can't explain, this absent God.'"

He continued, "A lot of the things people question most in our concerts are things we've lifted straight from Scripture. Like Ezekiel 16. Even WE cleaned it up - the Scriptures are even more graphic! But [the Church] tries to make the Scriptures safer."

Having a Lutheran pastor for a dad has no doubt shaped both Michael's love of theology and his view of songwriting. "I'm very careful to maintain orthodoxy in my lyrics because whenever we do concerts in churches I'm conscious we're getting people to sing these words and [singing] really affects what we think. That teaches theology."

This pastoral responsibility also comes from being Lisa's and Michael's roles as church leaders themselves. Having been part of the staff of a Michigan "mega-church", Lisa commented, "We just felt we weren't being true to what was in our hearts, staying there to have a good job, a good house. We felt we needed to give a lot of those things up to be true to what God was calling us to. We moved to Denver and started a church in our apartment. That grew and started to become a more public gathering."

Today, Bloom, Denver, has a congregation of about 200. "A bunch of hippie kids", Lisa described them, adding "it's so full of life, it's so rich. Every time we go home I feel it grounds me. We can breathe and get life back into our lungs where we're reconnected."

We've cleared up the meaning of "liturgical post-rock". What about the mystery of the title of the latest album, 'Ghosts Upon The Earth'? This concept album, with four movements travelling from the fall to new creation, takes its inspiration from C S Lewis. Explained Michael, "In The Great Divorce people take a tour of Heaven and everything is more real, more solid than they've experienced. The grass is so real it hurts their feet! A lot of the time we have our senses and think the things we can touch and see are the real things, but what if we're more like the ghostly reality on the earth longing to become real? What if God is the reality?"

It's a question worth asking. And Gungor's latest - with a switch this time to a more hushed, atmospheric recording - offers space to contemplate it amid some of the most arresting music the discerning listener will hear this year.