Progressive rock (1971–1976)
Drummer Clive Bunker quit the group in May 1971, citing heavy touring schedules and his wish to spend more time with his family. Bunker, who later went on to play for punk rock band Generation X, was replaced by Barrie Barlow, whom Anderson renamed "Barriemore". Barlow's first recording with the band was for the five-track EP Life Is a Long Song. Except for Barre, the line-up of Jethro Tull now consisted entirely of former members of the John Evan Band from Blackpool. In July 1971 Jethro Tull relocated to Switzerland to avoid increasingly strict UK tax laws and became tax exiles. The move put strain on Anderson's marriage to his first wife, which lasted for another year before they divorced.
Anderson became annoyed with music critics who described Aqualung as a concept album, which he had not intended it to be. "I always said at the time, this is not a concept album. It's an album of varied songs ... in which three or four are kind of the keynote pieces for the album, but [that] doesn't make it a concept album." He decided to "come up with something that really is the mother of all concept albums" in response. Influenced by the style of Monty Python, he wrote a suite that combined complex musical ideas with offbeat humour and made fun of the band, its audience and its critics. This album, released in 1972 as Thick as a Brick, consisted of a single continuous piece of music running for 43 minutes, spread over two sides of vinyl, an uncommon format for rock albums. It was written and recorded in stages, the whole band helping with arrangements, and was co-credited to a fictional schoolboy, Gerald Bostock. Thick as a Brick became the first Tull album to reach number one on the (US) Billboard Pop Albums chart. The following year's A Passion Play was the only other album by the band to do so.
Living in the Past was also released in 1972; it is a double-album compilation of remixed singles, B-sides and outtakes, including the entirety of the Life Is a Long Song EP, which closed the album. The third side was recorded live at New York's Carnegie Hall on 4 November 1970. The album was a success and allowed new fans to catch up with the band's early singles, particularly in the US where they had not been popular on initial release. New Musical Express called Jethro Tull one of "Britain's most important and successful 2nd generation progressive bands".
In the summer of 1972, the band attempted to record a double album at Château d'Hérouville studios in France, which the Rolling Stones and Elton John, among others, were also using at the time, but they were not happy with the studio and abandoned the project, subsequently referring to it as the "Chateau d'Isaster". They returned to England where in early 1973 they recorded and released A Passion Play, another single-track concept album, with allegorical lyrics focusing on the afterlife and, like Thick as a Brick, containing unusual instrumentation. The album also featured an eccentric interlude, "The Story of the Hare Who Lost His Spectacles", co-written by Anderson, Evan and bassist Hammond and narrated by Hammond. A Passion Play sold well but received poor reviews, including a particularly damning review of a live performance from Chris Welch of Melody Maker. After the negative reaction to the album, Anderson angrily shut himself away from all communication with the press.
While the band's popularity with critics began to wane, their popularity with the record-buying public remained strong, as was seen by the high sales figures of their follow-up album, 1974's War Child. Originally intended for the soundtrack of a film, War Child reached number two on the US Billboard charts, was given critical acclaim and produced two singles, "Bungle in the Jungle" (No. 12 on the US Billboard Hot 100) and "Skating Away on the Thin Ice of the New Day". It also included a short acoustic song with satirical lyrics, "Only Solitaire", which was believed to have been aimed at L.A. Times rock music critic Robert Hilburn, who had written a harsh review of A Passion Play concerts at the Santa Monica Civic Auditorium. Anderson said later that the song was written before Hilburn's review and was aimed at music critics in general. The War Child tour included a female string quartet playing on the new material.
In 1975 the band released Minstrel in the Gallery, an album in the style of 1971's Aqualung, which contrasted softer, acoustic guitar-based pieces with lengthier, more bombastic works reinforced by Barre's electric guitar. Written and recorded during Anderson's divorce from his first wife Jennie Franks, the album was characterised by a more introspective tone and received mixed reviews.
By this point in their career, Jethro Tull had been awarded five RIAA gold records for sales of Stand Up (1969), Aqualung (1971), Thick as a Brick (1972), Living in the Past (1972), A Passion Play (1973), and would earn a sixth for Minstrel in the Gallery (1975).
For the 1975 tour, Dee Palmer, who had long been the band's orchestral arranger, joined the band on stage on keyboards and synthesisers. And in February 1975, Jethro Tull sold out five nights at the 20,000-seat Los Angeles Forum, prompting Melody Maker to run the headline "Jethro – Now The World's Biggest Band?" Bassist Hammond left the band after the tour and was replaced by John Glascock from flamenco-rock band Carmen, who had supported Tull on several dates on the War Child tour.
Too Old to Rock 'n' Roll: Too Young to Die! was released in 1976. It is a concept album about the life of an ageing rocker. (On the Bursting Out live version of "Too Old to Rock 'n' Roll", released two years later, Anderson denies that the song is about himself.) Glascock made his first appearance as bassist with Tull on this album, and also contributed harmony and second vocals. Palmer continued as arranger, and appeared as a guest keyboard player on two songs. A television special was recorded showing the development of the album's concept in a live show, with the band dressed in tongue-in-cheek outfits, but was never officially released.
On the 1976 tour, Jethro Tull became one of the first bands to use giant projection screens in the larger stadium shows. Too Old... did not sell as well as the other 1970s albums, but the 1976 compilation M.U. – The Best of Jethro Tull, achieved Platinum Album in US and Gold record in UK.
