A theory of electromagnetism with uniquely defined potential and covariant conserved spin

The Lagrangian ½є₀c²∂_µA_ν∂^µA^ν is shown to yield a non-gauge-invariant theory of electromagnetism. The potential is uniquely determined by the inhomogeneous wave equation and boundary conditions at infinity. The Lorenz condition and minimal coupling follow from charge conservation. Electromagnetic spin is conserved and a spin operator is proposed without sacrificing covariance. Covariant quantisation is carried out without redefining the metric. It is a valid alternative to the standard approach since it makes the same experimental predictions.