Polarised positrons have a range of applications in moderb physics: from surface science measurements requiring energies as low as a few eV, to studies of the proton structure function and of the fundamental interactions of elementary particles at energies approaching the TeV scale. The common challenge for all of these studies is to generate sufficient numbers of positrons. A discussion of this topic is pertinent to these proceedings as it has been suggested that anti-protons can be efficiently polarised through a hyperfine spin-flip interaction with polarised positrons. In this paper I review the current state of high-intensity sources of polarised positrons. Emphasis is placed on those sources being developed to meet the requirements of future e⁺e^- colliders.