Smart meters could lose their functions if householders switch to another energy firm.

DECC told ELN people will be able to switch without problems once the national infrastructure is in place in April 2016, which means it could result in a one-year wait.

So far 1.5 million smart meters have been installed in people’s homes and this is not being properly explained to households, critics claim.

The gadgets record household energy use every 30 minutes and send this information directly to energy companies, meaning customers pay only for the gas and electricity they use.

Suppliers are obliged to install the meters in all their customers’ homes but they don’t have to make their smart meters compatible with those of rival firms.

Sacha Deshmukh, Chief Executive of Smart Energy GB told ELN: “Customers who already have smart meters may find that if they change suppliers before then their meter will temporarily need to operate as a traditional meter.

“But once the DCC goes live their meter will be bought into the network and be fully smart again, with no need for an extra visit from an engineer, or a new meter being installed.”

A spokesperson from Energy UK said they had no comment on the issue.