Bi8Pb5O17 shows a tetragonal (beta(2)) to body centred cubic (beta) transition, via an intermediate (phi), at 590 degrees C. The beta phase has high ionic conductivity, but reverts to beta(2) when cooled. This paper describes how phi can be stabilized to room temperature. We have used a range of physical and spectroscopic probes to show that beta(2) is stabilized at room temperature when the material is quenched from above 590 degrees C, and phi is stabilized when cooled from lower temperatures. We have compared the physical and electrical properties of these phases and discuss the possible advantage of stabilising the phi intermediate when fabricating devices from this material.