What was the purpose of the clock pulse in the Colossus computer?

In the design of the Colossus computer, the clock pulse was used to time and synchronize the machine's processing steps.1

This feature was a key innovation by the engineer Tommy Flowers. Unlike its predecessor, the "Heath Robinson" machine—which struggled with the difficulty of keeping two separate paper tapes accurately synchronized at high speeds—Colossus utilized a single paper tape and generated key data electronically. By incorporating a clock pulse to manage the timing of its internal operations, Colossus achieved significantly greater reliability and speed in its cryptographic calculations.1