One of the stalwart artists of the genre, Scottish flautist Ian Anderson, 66, looks set to enjoy his biggest hit for more than four decades.
Like many prog rock albums, Anderson's latest work is on a theme or concept — in this case the album, Homo Erraticus, delves musically into key events of British history.
These musical essays have proved popular enough to vault it into the top ten albums, according to the Official Charts Company's midweek update.
The album, which is presented in three sections, is currently standing at number six in the charts.
The record revives characters from his band, Jethro Tull, most famous album, 1972's Thick As A Brick and also muses on "Doggerland" the area that used to connect the British Isles with mainland Europe.
The Fife-born musician, who is reported to be worth £35 million, said: "If it is number six today, it will be 36 next week, then 1,006, but it's nice to be recognised in any context."
Prog rock flourished in the 1970s, when bands such as Yes, Pink Floyd and Genesis released long albums replete with multiple time-signatures, complex story lines and over-arching lyrical and musical concepts.
Its complex style and arcane lyrics were deemed to have been rendered obsolete when punk and disco became successful in the late 1970s, although modern bands such as Radiohead and Muse have dabbled in similar territories.
Anderson added: "Concept albums went out of fashion in the mid-1970s but progressive music is gathering strength again.
"Prog's bombastic, self-indulgent musical noodlings got a lot of people annoyed.
"It took punk to wash the system clean and make a fresh start."
He said the concept for the album was "migration" and added: "All of us are from somewhere else. But it's not a stern lecture."