Wilf's Solo (instrumental)

Whose song is Wilf's Solo (instrumental)?

Artist Album
Electric Light Orchestra
Electric Light Orchestra II
ELECTRIC LIGHT ORCHESTRA
ELO II (LIMITED EDITION 2-CD)
Electric Light Orchestra
Harvest Years 1970-1973
ELECTRIC LIGHT ORCHESTRA
The Harvest Years 1970-1973 (CD2 of 3)
ELO
The Lost Planet (Remaster)