It is shown that Dirac's new theory of gravitation and electromagnetism (1973) can be reformulated such that the scalar field is completely decoupled from the other dynamical variables. The symmetry breaking in Dirac's formalism is found to be unobservable.
Pietenpol, J. L., Incoul, R., & Speiser, D. (1974). Dirac’s new theory. Physical Review Letters, 33(6), 387-388. https://hdl.handle.net/2078.5/43046 (Original work published 1974)