This proposal is part of our research programme to explore novel ground states stabilized by frustrated interactions in quantum magnets. Here we plan to measure the spin dynamics in the layered honeycomb lattice antiferromagnet Li2IrO3. Strong spin-orbit coupling at the Ir4+ ion has been predicted to stabilize composite spin-orbital moments and this combined with the honeycomb lattice geometry could potentially lead to strongly-frustrated interactions that could stabilize exotic ground states, very different from the conventional 2-sublattice Neel order, including collinear stripe order and a so-called Kitaev quantum spin liquid with spinon excitations, none of which have been realized experimentally before. To test those ideas we propose to measure the spin excitation spectrum using MERLIN/MARI and compare with predictions for various spin Hamiltonians.