An experiment for the advanced undergraduate laboratory which allows students to study the effect of photon polarisation in Compton scattering and to explore q\ uantum entanglement is described. The quantum entangled photons are produced through electron-positron annihilation in the -state,
and their polarisations a\ re analysed using the Compton scattering cross-section dependence on the photon polarisation. The equipment necessary for this experiment is available at a typ\ ical undergraduate physics laboratory. Finite geometry effects are discussed and investigated with the use of a Geant4-based simulation.