A lot of very sophisticated stuff goes on in rock music and has been doing so since 1967 with Sgt Pepper and The Piper At The Gates Of Dawn. I’d just turned 20 and those albums were inspirational for me.

“It was an exciting demonstration that pop and rock music didn’t have to be so simple and trivial, but could still be hugely popular.”

It could never be described as a formula, but it’s certainly a path Jethro Tull frontman Ian Anderson has been following throughout his four-decade-long career – not least on his latest double album Homo Erraticus.

Following its release earlier this month, Anderson is taking the album on tour in a multimedia presentation, backed up with a second set of Jethro Tull favourites.

Homo Erraticus picks up on the story of Gerald Bostock – the star of Jethro Tull’s classic Thick As A Brick album, who was revisited on Anderson’s recent touring sequel.

The one-time Ian Anderson tour manager discovers an unpublished alternative history of British civilisation penned by Ernest T Parritt, entitled Homo Erraticus (The St Cleve Chronicles). Parritt, a former Army colonel stationed in India, was suffering from a recurrent bout of malaria as he penned the history, becoming convinced he had enjoyed past lives in the Neolithic era and as Queen Victoria’s consort Prince Albert.

Bostock turns the manuscript into a progressive rock album for his former charge Anderson to record, which goes from Doggerland in 7,000 BC to predicting the creation of a new Eden in 2044.

“I use too many words, cram lots of syllables and difficult rhythms in and find vocabulary that people are unfamiliar with,” admits Anderson as he prepares to film one of the tour’s multimedia sections.

“The language is filled with detail, analogies, allegory and simile. I’m using elements that are more familiar with the literary world but shouldn’t be excluded from rock music just because it’s rock music.

“I’m proud to call it progressive rock music – it has some discerning otherness about it. When it comes to being self-indulgent and going over the top, I’m entirely unashamed!”

The music occasionally touches on ideas from previous Jethro Tull albums – something Anderson is happy to admit, pointing to the fact Mozart and Beethoven did the same.

“If I’m doing something in a 12/8 time signature, I’ve got to make sure I don’t go into the same old territory,” he says. “You’ve got to be on your toes in the sense of self-awareness and self-analysis of what you’re doing. But you shouldn’t let that get in the way of the organic process of songwriting.”

It is clear he enjoys stretching himself as a lyricist – creating characters such as Bostock and Parritt to explore different ideas.

“I’m saying things with the lyrics on this album that I wouldn’t say in person,” he says. “They are not my sentiments – I wouldn’t use an expression like Johnny Foreigner – but I would in a song quoting the point of view of the Brit abroad.

“It’s part of the real world in which we live. The only way to approach it is with a smile on your face – to do it in a way that appears light-hearted for a dark subject. It makes it accessible but makes the audience think about it too. I’m not telling them what to believe but asking them to form their own opinions.”

Sticking to his guns

When it comes to his live shows, he is also refreshingly honest about who he is making them for.

“You’ve got to do something you believe in,” he says. “The audience has got to come second – after the other guys in the band, they come third! I’m not really out to impress an audience, I’m doing it for me.

“It’s a position of authority that audiences respect. You’re doing something because you find it challenging and rewarding. I can’t apologise for that.”

That said he is happy to trawl the archives for some old favourites in the second half – including some songs which haven’t seen the light of day in almost 40 years.

“A couple are among the most popular songs we had but we never played them live on stage,” he says.

“I have to overcome my own uneasiness about those songs – not necessarily musically but lyrically. As a songwriter, I don’t feel they’re near my best, so I try to concentrate on the bits of the songs I do like and am proud of.

“In my old age I’m more capable of putting up with my old feelings of the past – obviously they sounded good to me at the time!”