RELAXED, charming and easy-going, Gaz Coombes is one of the good guys of British indie-rock – with an easy laugh and a cheeky grin. So it comes as a bit of a surprise to learn that when it comes to writing, this friendliest of musicians prefers to spend large chunks of his time completely alone.

Take latest album World’s Strongest Man which started life with just Gaz hiding himself away in his studio at home in Wheatley, playing all the instruments himself.

“It started off in isolation with me embracing the solitude and my stream of consciousness,” he tells me, on a rare moment of down time between gigs.

“I record early takes from the moment I write, but tap into other people’s expertise the moment I don’t know what I’m doing!

“The first part of recording the album is chaos and the second part is more scientific, and sees it all coming to fruition.”

To record the album he dragged everything upstairs from the basement studio of the house he shares with his wife Jools and daughters Raya and Tiger – the family living among a tangle of drum machines, synths and leads.

He also put in shifts at his second home, The Courtyard Studio in Sutton Courtenay, working with long-time producer Ian Davenport.

Among those helping out was another Courtyard regular, Radiohead’s Colin Greenwood.

“Colin came round and over a bottle of wine I asked him to play bass,” laughs Gaz. “There was a lot of collaboration towards the end; a lot of musically-minded people rolled up and joined in.”

They included live band collaborators Mike Monaghan, Garo Nahoulakian and Nick ‘Growler’ Fowler – who will be joining Gaz when he returns to his roots for a set at this weekend’s Truck Festival, in Steventon.

The festival was the scene of a triumphant show by his old band Supergrass in 2009. A year later the band broke up and Gaz stepped out as a solo artist in his own right.

After 17 years together it represented a step into the great unknown. It also represented the start of an equally fruitful new stage of his career.

While still proudly sporting those same familiar sideburns, Gaz has long since stepped out of the shadow of his chart-topping Mercury, Brit and Ivor Novello award-winning band, to recast himself as a groundbreaking singer-songwriter in his own right.

His 2012 album Here Come The Bombs, saw him branching out into new territory unencumbered by the collective responsibility that comes from being in a successful band with an adoring fanbase. That was taken to another level with 2015’s Matador. Cinematic and packed with new ideas it saw him forging a new identity and it earned him a Mercury Prize nomination in the process.

With World’s Strongest Man he has delivered his magnum opus – a work which cements his position as one of the world’s greatest songwriters and as an accomplished multi-instrumentalist.

Multifaceted and inventive, it sees Gaz at the top of his game and defies categorisation. There’s Americana, rock, post-punk, electronica, driving rhythms, hazy psychedelia and those trademark choruses which hold their own next to anything he did with Supergrass.

The title was inspired by Grayson Perry’s book The Descent of Man, in which the cross-dressing potter attacks the concept of masculinity. Indeed the title track explores the contradictions of masculinity: “I’m a little messed up / I’m the world’s strongest man / Call me if the fire starts / don’t call me when it gets too hot…”

“It’s about an adult human being who wants to be all these things but has weaknesses,” says Gaz who admits to being "quite good” at being messed-up.

“It’s not all laid out in front of me perfectly,” he says. “I wanted to get that across by being open and honest.”

Themes of flawed masculinity are expanded in Walk The Walk with its Donald Trump-like imagery of “misguided, delusional men that are making it worse for everyone else.

“Imagine freeing men from those constraints of being [idiots]! Imagine what they could do…”

There is politics, of a sort, and much of what bothers him about the world, but also existential moments of doubt or reaffirmation – of losing it (Vanishing Act is his “breakdown song”), finding it, and moments of pure autobiography.

It demands to be listened to on repeat.

There is a lot of Oxfordshire in the music too. The Oaks, for example, sees him revisiting his thoughts following his mother’s death in 2005 – when he decided to move back to the family home in Wheatley. The name refers to a clump of trees he’d walk to near the village.

He says: “Oxfordshire is there in the themes and lyrics, in the artists I work with – there’s a lot of creativity in this area. But it’s also the birds in the garden and the environment I’m in.

“Life is pretty manic and I travel around and see a lot of places and some really interesting cities, but in Oxford I have space to process those experiences.

“Oxford is home and comfortable and gets the best out of me and my writing.”

Tomorrow’s Truck show comes off the back of heavy worldwide touring. With such a manic schedule, how does he manage to keep his head together?

“I don’t!” he laughs.

“It is with difficulty,” he goes on. “There are certain elements I’m used to and when you get to the point of the album being released it all ramps up and a lot happens. But I really enjoy it and feed off the fans. It’s all very rewarding.”

And how does he look back on his time in Supergrass – who, least we forget, were one of the biggest bands of the 90s, scoring six top 20 albums, three of them platinum – including the seminal I Should Coco, which was the biggest-selling debut for Parlophone since the Beatles released Please Please Me in 1963.

“It seemed important in the beginning to make a separation so I was not seen to be living off some kind of legacy. Rather than speaking about it all the time I like to show what I’ve done. It’s a new thing and it should be seen without baggage. The shows are not based around Supergrass songs and the response has been great.

“But I am feeling more open about talking about the stuff I did with Supergrass. There are things I am proud of and we had a great time.”

And how does it feel to be returning to Hill Farm for Truck?

“It’s great to be asked to go back to Truck,” he answers. “I’m really looking forward to it. And I’ll definitely be hanging around!”

  •  Gaz Coombes plays Truck Festival tomorrow. The festival runs from tonight until Sunday. Go to truckfestival.com.
  • World’s Strongest Man is out now