Clarkin’s death came just a week after Magnum released new song The Seventh Darkness.
It was taken from the upcoming studio album Here Comes The Rain, which is due for release on Friday.
“The recordings were great fun, especially the moment when Chris’s sax took the lead and my guitar responded,” Clarkin said in a press release announcing the single.
The prolific band have released 22 studio albums over their five decades.
Among them is 1988’s Wings Of Heaven, which sold more than 60,000 copies and reached number five on the UK album charts.
The cancelled tour had been due to visit KK’s Steelmill in Wolverhampton.