Bono thinks U2 "failed the mainstream" with their last two albums.

The 66-year-old rocker has insisted 2014's Songs of Innocence and 2017's Songs of Experience were filled with "really great" tracks but admitted the band struggled to find a "cohesive sound" for the records.

He told NME: "I would say that there's a part of me that felt that we failed the mainstream with our last two albums [Songs Of Innocence and Songs Of Experience]. You only have a certain amount of agency with that audience. The perfect song, the perfect punk rock song for instance, it is my drug of choice.

"We went in on those two albums and wrote really great songs, we just couldn't find a cohesive sound to those two albums. The songs were great and the thematics were right. Though they weren't autobiographical and I don't know if this is a contradiction, but they weren't self-indulgent.

"But that doesn't matter, because people just feel things."

The Vertigo group are back with new album Carnaval de Luz and when recording with Brian Eno, they tried not to focus on crafting songs that will be played on the radio because they're not convinced they'll get airplay any more anyway.

Bono said: "We don't know if enough people play U2 on the radio any more. Are people even interested in radio? For those two albums, it was hard to give up that idea.

"Maybe it's just not for us anymore. That's been taken away from us, that opportunity, and we just let it go.

"We get into the sandpit. We're like kids with Brian Eno again as soon as we start making this mess. It all coagulates and the pieces start to fit with this idea of carnival, which we've always carried around with us."

Meanwhile, with Fontaines D.C. being branded as the "biggest Irish band since U2", Bono and bandmate The Edge are delighted for the group's success and admitted it only drives them to do better too.

Bono said: "It's incredible to see them doing stadiums, they're so great.

"It all should make you up your game. Bands make each other better if they're any good. I can't imagine The Beatles being as good as they were without The Stones, I can't imagine The Stones being as good as they are without The Beatles. Paul [McCartney] writes Let It Be then they put out an album called Let It Bleed, you know, All You Need Is Love and then Street Fighting Man.

"In the '90s you had Blur and Oasis. You make each other better. I will admit that when you hear something really unique and original. That song [Edge] played me recently…"

The Edge interjected: "Lambrini Girls. I'm just so jealous of them. Now that's a sound I would love to hear on a U2 album. Just the sonics are fantastic."

Bono added: "That's it. You have to up your game when people step into the room like Fontaines D.C."