A key IT project at the heart of the national smart meter roll-out programme is facing further delays.
The government has confirmed that the communications infrastructure which links smart meters to energy suppliers will now not be ready until the Autumn.
The system was due to be switched on on Wednesday.
The government says the system, which automatically sends meter readings to energy suppliers, is now due to go live at the end of September.
That requires 53 million meters to be fitted in over 30 million premises over the next four years.
The meters will measure gas and electricity use and automatically send meter readings to energy suppliers, ending manual meter readings.