Episode 63 of The Trigan Empire
The Frozen People
aka De klauwen van het verleden (Dutch title)
The Claws of the Past (Dutch title, translated)
Written by Mike Butterworth
Illustrated by Oliver Frey
The Frozen People was originally published in 10 instalments in issues 782 (8 January 1977) to 791 (12 March 1977) of Look and Learn magazine.
To date it has not been reprinted in English.
Links
783
https://www.2dgalleries.com/art/look-learn-783-the-trigan-empire-art-by-oliver-frey-183595
Plot summary (Dutch)