We investigate the effects of spontaneous breakdown of CP in B 0 d , s - B 0 d , s systems in left-right symmetric models. Assuming that the left-right contribution to the B 0 - B 0 matrix element M 1 2 can be at most equal to the standard model one we obtain a new lower bound, M H 12 TeV, on the flavour-changing Higgs boson mass. Most importantly, the convention independent parameter Re( B ), which measures the amount of ΔB = 2 CP violation, can be enhanced by a factor of four or more for B 0 d and almost by two orders of magnitude for B 0 s systems when compared with the Standard Model predictions. Therefore, interesting possibilities to observe indirect CP violation in the B system are open in the planned facilities.