Competition from rivals such as Petter, and from overseas were also factors to be contended with, and in 1965 Listers was acquired by Hawker-Siddeley (see below) who had also bought its old rival Petter in 1957.
Competition from rivals such as Petter and from overseas were also factors to be contended with, and unauthorized copycat engines ("Listeroids") were produced in other countries. In 1965 Listers was acquired by Hawker-Siddeley (see below) who had bought its old rival Petter in 1957.