Deep Purple performed at the City Hall in Sheffield on this day in 1971.

At this time in their career, Deep Purple’s Mark II had already released two successful albums of wildly different genres with a third, Fireball, at least partially recorded and slated for release later that year. In short, they were very much on the ascent!
The tour on which they were performing, the In Rock World Tour, had been going since the previous July. It was mostly to support their first proper hard rock album, the titular Deep Purple in Rock, and was the second major tour that Mark II undertook.

A typical Purple concert on this tour was, on paper, very short. Setlist.fm only records eight songs. There is no way for sites to quantify how long they would have taken to improvise between songs, however! Long instrumental performances in-concert were what made this lineup famous, often with instruments meandering for long lengths of time, sometimes together and sometimes separately. Ian Paice often took a short but electric solo during “The Mule” during this period. Jon Lord and Ritchie Blackmore would stretch theirs out more, with Lord usually sprinkling Dvorak’s New World Symphony within his solo.
Interestingly, a full four of the eight songs listed for the setlist were off the forthcoming album! Only were off In Rock, the album they were ostensibly touring to support. Two further songs would not appear in print until Machine Head hit the shelves in 1972. Deep Purple, then as they are now, were ever in motion.
There is no known recording of the concert.
I talk more about the venue at which they performed, the Sheffield City Hall, here.