The CLASS blazar survey. I - selection criteria and radio properties

This paper presents a new complete and well defined sample of Flat Spectrum Radio Sources (FSRS) selected from the CLASS survey with the further constraint of a bright (mag<17.5) optical counterpart. The sample has been designed to produce a large number of low-luminosity blazars in order to test the current unifying models in the low luminosity regime. In this first paper the new sample is presented and the radio properties of the 325 sources contained therein discussed.