A method for verifying the correct formation of the beads in a process and a plant for building tyres for vehicle wheels, includes: loading a plurality of annular anchoring structures in a storage, disposing them in two groups separated by an opening; positioning a building drum provided with a carcass sleeve in a tyre bead-forming machine; picking up two of the annular anchoring structures from the storage and loading them on the tyre bead-forming machine. In a work area of the tyre bead-forming machine, on each of two axially opposite zones of the carcass sleeve, a respective annular anchoring structure is fit and each of the abovementioned zones is turned up around the respective annular anchoring structure to form the beads. The aforesaid opening allows an operator to conduct a visual inspection of the work area and/or access the work area during the entire work cycle of the machine.