We demonstrate a concept for the giant enhancement of the transverse magneto-optical Kerr effect (TMOKE), with amplitudes reaching the maximum theoretical values of $\ifmmode\pm\else\textpm\fi{}1$. The concept exploits the strong electromagnetic field localization in $\ensuremath{\varepsilon}$-near-zero metamaterials to excite surface plasmon resonances with no need of a prism or grating coupler, thus opening routes for magneto-optical devices amenable to miniaturization. A demonstration of the capability of the enhancement mechanism is presented in which giant TMOKE values can be used for sensing and biosensing.