The invention relates to a cap for the neck of a container and to a method for producing one such cap. According to the invention, the skirt (12) of the cap (1) is provided with frangible bridge elements (44A, 44B) which break when the cap is first opened. In addition, on either side of the aforementioned frangible bridge elements, the skirt includes a non-removable part and a removable part provided with an outer biasing tab (24) that only extends along a peripheral portion (12A) of the skirt. In order to limit the biasing force of the tab, so as to release the removable skirt part, the radial dimension (e44A) of the bridges (44A) located in the skirt portion (12) associated with the tab is smaller than the radial dimension (e44B) of the bridges (44B) located outside said portion.