Simpson has altered Regerís 12/8 metre to a 3/4 pulse, and treated the original (which first appeared in a vast ritenuto) as an allegro. Like Brahms in the great passacaglia from his Symphony No 4, Simpson has changed one note only, so as to make the bass combinable with a series of rising fourths, a feature strikingly evident in his Symphony No 9, the work that immediately preceded this Introduction and Allegro.
The extended slow introduction, Adagio ó Pesante, is mysterious, awesome, based on fragments from Regerís bass which emerge in many different forms and different melodic shapes throughout. After a big climax is reached, a stabbing repeated-note figure provides a link into the main Allegro vivace where the Reger bass is presented complete for the first time. Other themes are also introduced which show the rising fourth as a prominent interval. The final section is a thrilling crescendo of almost Brucknerian intensity, which uses Regerís own treatment of his bass at its peak, providing a thunderous culmination to one of the most impressive and challenging works in the entire brass band repertoire.
from notes by Matthew Taylor © 1991