  Within the Minimal Supersymmetric Standard Model we study the three body
decay of the lighter top squark into a b-quark, a W-boson and the lightest
neutralino and compare this decay with the flavour changing two body decay of
the lighter top squark into a c-quark and the lightest neutralino. We do this
for scenarios where two body decays at tree level are forbidden for the light
top squark. We give the complete analysis for the three body and compare it
with the mentioned two body decay. We discuss our numerical results in view of
the upgraded Tevatron, the LHC and a 500~GeV $e^+ e^-$ Linear Collider.
