The case follows an identical one launched on behalf of iPhone users in May.
Google said it competed “vigorously and fairly” for developers and consumers and its fees were “comparable to our competitors”.
Most Android phones came pre-loaded with quite one app store.
And 97% of developers paid no service charge because their apps were free.
“This lawsuit ignores the advantages and selection Android and Google Play provide also because the competitive market during which we operate,” it said.
Google recently cut its service fee to fifteen for all developers earning but £1m, with only a small fraction of the foremost profitable app developers paying 30%.
The charge “allows us to constantly reinvest in building a secure, thriving platform that benefits everyone who uses it”, it added.
But both Apple and Google’s charges have come under intense public scrutiny, following a huge row with Epic Games and subsequent action .
Epic argued the Play Store and Apple’s app store were monopolistic and is seeking the power to put Fortnite on both, with an independent payment-processing system.
This UK action alleges:
Google broke European and UK competition laws with the 30% surcharge and as a result’s overcharging many app users who make purchases via the Play Store.
because Google bundles the Play Store with other products and requires pre-installation of it, consumers have little alternative but to pay the fees began by Google
The claim has been filed with the Competition Appeal Tribunal (CAT), by former Citizens Advice consumer-policy lead Liz Coll.
The CAT has allowed “collective actions” – almost like US-style class-action cases – subject to initial approval, since 2015.
They differ from normal legal cases therein all affected people are automatically covered unless they plan to exclude themselves.
Ms Coll said: “Google created the Android app marketplace and controls it with a vice-like grip.
“Customers are herded towards the Google Play Store and, once there, haven’t any option but to pay a 30% fee whenever they buy an app or make an in-app purchase.
“Competing app stores, which could give an equivalent service at a fraction of the worth , never get a glance in.”