We solve the linearised Vlasov-Fokker-Planck (VFP) equation to show that heat flow or an electrical current in a magnetized collisional plasma is unstable to the growth of a circularly polarised transverse perturbation to a zeroth order uniform magnetic field. The Braginskii [1965 Rev Plasma Phys1 205] transport equations exhibit the same instability in the appropriate limit. This is relevant to laser-produced plasmas, inertial fusion energy (IFE) and to dense cold interstellar plasmas.