The rollout of fully-functional smart meters has been further delayed after “teething issues” with the system.

This week, the Government announced that the deadline by which energy suppliers must stop installing first-generation smart meters would be pushed back. More than half of these meters lose many of their functions when a customer switches provider.

The two-month delay means almost a million more of the substandard meters will be installed, bringing the total number above 13 million.

The new type of meter, which will be connected to a national communications network to allow easy switching between energy providers, was initially supposed to be widely used from July. But that date has twice been pushed back and, so far, only about 26,000 have been installed, according to figures from industry analysts ElectraLink.

The delay was expected, but was only officially announced this week.

Telegraph Money can disclose that a number of second-generation meters, believed to be in the low thousands, have already been replaced within months of being installed.