The British singer and songwriter's new album Once Upon A Mind is, he says, "the album of his life". In it, he takes a fresh look at the things that matter most to him as a musician, a man, a husband, a father and a son.

"Certain things have happened that I've needed to write about," he says. "It's gone back to not being a job, and not just messing about with music. There are things I very much needed to get out. And that's why it's a very different album."

His 2004 debut Back To Bedlam was the quiet album that roared. Followed by All The Lost Souls, Some Kind of Trouble, Moon Landing and The Afterlove - and 23 million album sales later - Once Upon A Mind is a return to what Blunt does best.

It's raw, honest, emotionally charged and melodically rich. It's Blunt having come full circle.

"This album has been a pleasure. I'm making music for the reasons that I got into music in the first place," he says.

"It's kind of unfiltered and I'm exposing myself in a way that you are meant to when you're making music. I would say that my first album was the same; it was about me having just left the army, and not thinking that there was going to be an audience. I was just writing songs about trying to find my place in the world.

"You write the songs and you put them out, that I love, but talking about them and describing them in interviews I've always found hard. Not with this album and these songs. I'm very much more open because it would do the songs and the people these songs are about a disservice if I didn't spell it out and explain what they're about. And weirdly, I suppose, because I was not thinking about writing words for an audience, I think they will probably connect with this one much more."

One catalyst for this soul-searching was his father's illness. He has stage four Chronic Kidney Disease. Blunt says he realised he had "thoughts he needed to get out" and these became the driving force of the album.

"It gave me a focus. When you realise the mortality of a parent and it coincides with having children, you see the circle of life more clearly," he explains.

"With my Dad not being very well at the moment, and me having a new little family, I can see the circle of life and time playing out in front of me. I don't have much time left with my Dad and I haven't had a lot of time with my family because I tour for extended periods of time, and I realised there are consequences.

"So, with this album, I wasn't writing with an audience in mind, I'm just using music to talk to the people that I'm leaving behind."

One example is the track Monsters with lyrics like: I'm not your son, you're not my father, we're just two grown men saying goodbye ... No need to forgive, no need to forget, I know your mistakes, you know mine.

Blunt repeats them during our chat, cementing their importance in his mind.

"For me, a song like that has been an amazing opportunity," he says.

"There are chapters in your life. When you become an adult you no longer idolise your parents because you realise that they have failings too, and it's a great moment because you can then be equals and friends rather than being blinded by the love you have for them. Then they get more frail, and to look after them is another amazing, sad, but beautiful chapter. Again, it's the circle of life."

Blunt's ever-present sense of humour is endearing. It has actually won him fans over the years, with his Twitter posts the stuff of legend. Try to bring him down, you will fail. His razor-sharp wit means he has an answer for everything.

The video for first single Cold, for example, shows Blunt emerging from the ocean wearing what appears to be the same trousers and T-shirt he did for the You're Beautiful video 15 years' prior. It turns out they are the same trousers and shirt.

"You know what? I had those clothes from the You're Beautiful video hanging in my cupboard for 14 years," he says with a laugh.

In the video he climbs up a hill and finds his possessions from You're Beautiful. Then, a helicopter takes him away. It's symbolic for Blunt. He feels free and with that freedom comes power, confidence and creativity.

"Before this new album it felt like I had been lost at sea for 14 years, not really opening up in a musical way. Now I feel I am finally making my way back to shore."