Sensitivity to $\theta_{13}$ of the CERN to Gran Sasso neutrino beam

The sensitivity of the present CNGS beam to the sub-dominant $\nu_\mu \leftrightarrow \nu_e$ oscillations in the region indicated by the atmospheric neutrino experiments is investigated. In particular, we present a revised analysis of the OPERA detector and discuss the sensitivity to $\theta_{13}$ of ICARUS and OPERA combined. We show that the CNGS beam optimised for $\nu_\tau$ appearance, will improve significantly (about a factor 5) the current limit of CHOOZ and explore most of the region $\sin^22\theta_{13}\simeq\mathcal{O}(10^{-2})$.