  The 1998 outburst of the bright Galactic black hole binary system XTE
J1550-564 was used to constrain the accretion disc structure in the strongly
Comptonised very high state spectra. These data show that the disc emission is
not easily compatible with the constant area L ~ T^4 behaviour seen during the
thermal dominated high/soft state and weakly comptonised very high state. Even
after correcting for the effects of the scattering geometry, the disc
temperature is always much lower than expected for its derived luminosity in
the very high state. The simplest interpretation is that this indicates that
the optically thick disc is truncated in the strongly Comptonised very high
state, so trivially giving the observed continuity of properties between the
low/hard and very high states of Galactic black holes.
