With the introduction of competition into residential gas supply, interest in the gas meter and metering services has increased. Following an initial focus on the selling price of gas, there will be a need for gas suppliers to differentiate themselves from their competitors by value-added products and services. In metering, this has led to the concept of a `modular meter'. This would allow a meter owner to install a base model meter and as additional metering services are required, a module can be added by a `clip-on' attachment. There have been discussions between meter manufacturers, gas suppliers, Transco and Ofgas, to arrive at some general aspects of the requirements for a modular meter and attachments, but without conclusions on the detailed technical specification. BG Technology are promoting a situation in which the modules can interface to any type of residential meter (E6, U6), and this should provide universal access and ensure that competition is enabled for provision of any metering service.