The use of a plasma mirror to improve the temporal contrast of few cycle laser pulses has been considered. Pre-plasma features, prior to the main pulse, have been evaluated using an analytical model that has been verified using hydrodynamic code. The temporal/spectral profile, reflectivity, and broadening of the reflected pulse have been parametrically analysed using an analytical formulation that describes the reflection of broadband ultra-short pulses from the plasma gradient. The analytical estimate for the pulse reflectivity is in good agreement with experimental measurements. The consistency of the analytical expressions for the collisionless case has been validated via comparison with a 1D particle in cell simulations.