  Neutral-current ({NC}) and charged-current ({CC}) deep inelastic scattering
({DIS}) reactions have been studied in $e^+p$ and $e^-p$ collisions using the
{H1} and {ZEUS} detectors at {HERA I}. Following the upgrade of the {HERA}
accelerator, the {HERA II} program recently started with the first data in
$e^+p$ scattering with longitudinally polarised positrons. In this paper, a
summary of the electroweak results from {HERA I} and the first measurement of
the cross section for $e^+p$ CC {DIS} at a longitudinal polarisation value of
33% from the {ZEUS} collaboration are presented.
