The apparent rift between Tull frontman Ian Anderson and the guitarist seems unlikely to be bridged any time soon, and so, for Martin, now is all about new beginnings.
"[Jethro Tull] is broken," Martin told me, as New Day rehearsed for their UK tour. "Sometimes I feel quite empty. Something that supported you for that long it becomes second nature. Then it's gone; you can never prepare for that. It's like someone retiring, and they feel the ground's been taken from under them.
"That's one side, but on the other side I have got total freedom; I get to set my own schedule. It makes my life a lot more happy because I'm dealing with things that I'm in control of."
The seeds of the apparent demise of the Anderson-Barre partnership were sown this year when Ian took on tour Tull's seminal Thick As A Brick album alongside his solo sequel, Thick As A Brick 2, without Barre or Tull drummer Doane Perr. It was a decision which surprised many fans.
Martin said: "It's difficult, it's not just something that you take for granted, that [the band] can end and you can go on and do other things. You stop doing this huge entity that's supported you so well It's really starting from absolute scratch."
Starting from scratch, for Martin, doesn't mean chucking away the 40-plus years of musical history he made with Jethro Tull. Instead, the 66-year-old has put together a band to play blues favourites and older Tull tracks, with a group of younger musicians, for an intimate tour of venues round the country. Martin admitted that during rehearsals with his band - made up of drummer George Lindsay, guitar player Pat O'May, bass player John Noyce, sax/flute player Frank Mead and singer Dan Crisp - he discovered that teaching others how to play Tull's often complex prog folk wasn't always easy.
"The music is pretty complicated; I guess I have taken it for granted, being brought up on it for 40 years," he explained. "And then you start involving people from outside and realise how difficult it is. They have problems learning it and understanding. It's quite difficult and it takes a lot of time.
"The songs we are doing, probably about eight or 10 are Jethro Tull bits of music, but songs that have not been played for 20 or more years because they are the more rock-sounding side of Jethro Tull.
"It's exciting to do those things. And the rest of it is made up of my favourite old blues standards. I love being able to arrange music and organise it. It's the cream on the cake. It's so much fun to do that."
He revealed that getting to play the rockier Tull tunes was liberating: "It's a very exciting show, musically - it's heads-down and enjoy the music. It's a good atmosphere and that's something that's been missing from things I have been doing for the last few years. It was getting more and more similar and safe and quiet in Jethro Tull. [This is] back to the roots of being in a band."
Martin Barre's New Day play Arlington Arts Centre on Saturday, at 8pm. Tickets cost £17.50 from www.arlingtonarts.com or call 01635 244246.