Claimant lawyers say they filed court documents at the Competition Appeals Tribunal against Vodafone, EE, Three UK and O2 last week. The claims accuse the phone companies of overcharging on as many as 28.2 million contracts by not reducing the amount customers had to pay after their minimum terms expired, despite them having effectively paid off their mobile devices.

The claim consists of individual lawsuits against each company, with damages sought of up to $1.76 billion from Vodafone, up to $1.38 billion from EE, up to $637.8 million from Three, and up to $322 million from O2.

Claimant lawyers at Charles Lyndon, a law firm, estimate that up to 4.8 million people could be affected. If the case is successful, someone who held a contract with one of the mobile operators could receiveÂup to $2,293.

The claims are on an "opt-out" basis, which means all qualifying customers will be automatically included in the claim unless they make a choice not to join.