Would 20 mm guns replace British half-inch machine guns?

Would the Royal Navy replace its half-inch machine guns and older low-velocity pom-poms?

Replacement by 20 mm weapons is considered likely, with older low-velocity weapons also under pressure.

The longer interval offers time to replace the half-inch mounts. The answer also envisages a more powerful pom-pom development with performance closer to Bofors. That is a possible development direction, without a fixed fleet-wide completion date.