However we assert that the first London equation, relating the time derivative of the electric current to the electric field, describes the behavior of "perfect metals" but it does not describe the behavior of superconductors.
The only experiment ever performed that appears to support the first London equation, as of December 2003, is an experiment performed by H. London in 1935 (Proc. Roy. Soc. A 155, 102 (1936)). It has never been repeated.
The theory of hole superconductivity leads to a new description of the electrodynamics of superconductors and predicts that 1) The first London equation is incorrect, instead the gradient of the electrostatic potential should be added to the electric field; 2) an internal electric field exists in superconductors that does not give rise to an electric current; 3) an externally applied field is screened over a distance given by the London penetration depth at low temperatures, rather than by the (much smaller) Thomas Fermi screening length, 4) a spontaneous electric field exists superconductors of non-spherical shape.