  We investigate star formation occurring in idealised giant molecular clouds,
comparing structures that evolve in isolation versus those undergoing a
collision. Two different collision speeds are investigated and the impact of
photoionising radiation from the stars is determined. We find that a colliding
system leads to more massive star formation both with and without the addition
of feedback, raising overall star formation efficiencies (SFE) by a factor of
10 and steepening the high-mass end of the stellar mass function. This rise in
SFE is due to increased turbulent compression during the cloud collision. While
feedback can both promote and hinder star formation in the isolated system, it
increases the SFE by approximately 1.5 times in the colliding case when the
thermal speed of the resulting HII regions matches the shock propagation speed
in the collision.
