Mr Vande Lanotte believes many consumers will be able to make savings: "We've done the figures. It could save consumers up to 40 euros a month."
Proximus, Mobistar, Base en Telenet/VOO have given an undertaking that they will contact 90% of their customers who qualify by September. Some 800,000 mobile phone customers could benefit.
A campaign to encourage people to move to a more advantageous tariff plan is being launched under the name 'Switch and Save'. It will be monitored by the Belgian telecom watchdog BIPT. An earlier campaign got customers to make 360,000 price simulations.