'We've just not been in a rush, really,' says Jason Swinscoe, joint bandleader of definitive Ninja Tune signees The Cinematic Orchestra, who are celebrating their twentieth year in existence this year. They're also back with their fourth album To Believe, the first full-length of original music they've recorded in twelve years, since 2007's Ma Fleur. He isn't exaggerating when he implies they've been taking their time.

'We've been working and writing a lot, been out doing shows, but we felt it was important to wait until we're ready,' Swinscoe continues, doing the promotion rounds by phone alongside his co-composer Dominic Smith. 'Every Cinematic Orchestra record is very carefully considered and put together, there's no quick turnaround involved in the process of creating one. We're very conscious of the hiatus, but we wanted to come with a good record, and creating good music takes its time.'

'On every record, particularly after the first record, there's a part of you that's trying to push the narrative you've already created in a really authentic way,' concurs Smith. 'Not to break what's happened, but to evolve it, and find new ideas which will resonate with people and will last, not just now but in the future. Music has a way of dictating what it wants to be and there's a conversation you have with it, and the more albums the band put out, the more questions need to be asked and the more answers need to be provided.'

The Cinematic Orchestra were formed out of the nu-jazz scene, within which Swinscoe and Smith were firmly entrenched at the time (both worked for Ninja Tune), yet their sound has taken on a more expansive scope to fit the ambition of their name. Their live shows are pocket orchestral performances, and their music encompasses rich, dense flights of sonic fantasy which have been lent to television, film and advertising. The new record features vocal contributions from singers including Roots Manuva, Heidi Vogel and Moses Sumney, and is themed around the idea of belief.

Swinscoe says that Sumney was the first guest picked, and discussions held by the trio around the title track informed the rest of the album. '[The theme] was born out of our own feeling that there was a lack of interesting political narratives in music,' he explains. 'It felt like music was losing its place as a critical voice, that it was becoming more and more commercial, more accessible, that what was underground had gone overground. We started writing this record at a time when it wasn't so obvious that there are as many political divisions as there are, but there was still a lack of that conversation.'

All the things that have transpired over the last few years in the US and the UK have magnified the questions this music is asking, but Swinscoe says it's coincidence that they happened in tandem with the record's creation. 'What we discuss is on a more fundamental level, about how you make up your mind what it is you believe in,' he says. 'It's the idea that belief is a creative act, and that reality is the result of our imagination. There are many different disciplines which explore that appreciation of existence, and it's something which resonates with both of us on every level. I think that human beings could definitely do with more self-contemplation and we could all evolve a bit, be more analytical about the way we think and form opinions.'

Swinscoe describes the live show as being a seven-piece group, including himself and Vogel as touring vocalist, with an emphasis in parts upon the improvisational, jazz-influenced element of their work; occasionally other guests like Sumney or Tawiah may also appear, depending on their schedule. It's an expansive end result for music which he and Smith composed on the move, in Los Angeles, London and a Paris hotel room.

'Wherever we can set up on a table with some speakers and a mic, and some quiet time with no stress from neighbours. we can work,' says Swinscoe. 'It's actually quite a freeing experience, to feel you're not on the clock in the studio and don't have to fulfil an idea right away. We take our time to revisit, finesse, refine. We spent a good couple of years just writing, then started to pick certain tracks to develop; we have a lot of material, and this is just the first selection on this record.

'We don't really measure our recording in terms of time and years,' he says, when asked to put a figure on how long To Believe took. 'It's an ongoing creative, critical process that takes as long as it takes, and it's ready when it's ready. I think that a sense of timelessness is part of our constant conversation with music.'

To Believe is out now on Ninja Tune. The Cinematic Orchestra are on tour around the UK now, including at the Royal Concert Hall, Glasgow, Tue 26 Mar.