U2 has used an interview with Rolling Stone to apologise, once again, for the Songs of Innocence / iTunes debacle and to detail what is coming in the next couple of years.

Songs of Innocence was offered free by U2 and Apple for four weeks to anyone that had an iTunes account. The intention was that the album would be made available to users but, instead, some found that the set was automatically downloaded onto their phones, iPads, etc. creating what Bono described as a 'shitstorm.'

The singer told Rolling Stone 'It's like we put a bottle of milk in people's fridge that they weren't asking for. It is a gross invasion but it was kind of an accident. The milk was supposed to be in the cloud. It was supposed to be on the front doorstep.'

Bono also laid out the band's plans for the next few years. Originally, there had been rumors that the followup, Songs of Experience, would be out soon after Innocence; however, he is now saying that it will hit the streets about 18 months from now. They will then follow, sometime after Experience, with Songs of Ascent, completing a trilogy of albums. The singers says of the last album that 'there are some beautiful songs.'

The full interview is in the upcoming issue of Rolling Stone with U2 on the cover.