UK households will be permitted to use the devices – expected to cost around £350 to £400 – from 27 August after Labour ministers pushed through legal changes last month.

They can shave between £70 and £110 off annual energy bills – allowing the panels to pay for themselves in just four years.

Retailers such as Lidl, Asad, B&Q, Currys, Screwfix and Wickes have all expressed interest in selling panels which come with a self-install plug attached.

None of the firms has set a specific launch date for the solar devices.

Electrical safety advocates told The i Paper there had not been much time for manufacturers to follow the product specification rules set out by the Government last month. Devices also need to be registered with the Energy Networks Association (ENA).

However, Government officials do not anticipate any regulatory hold-ups and expect the products to be available to buy at the end of this month, The i Paper understands.

“Plug-in solar panels will be available to buy this summer, and stringent verification and registration checks are already in place,” said a spokesperson for the Department for Energy Security and Net Zero (DESNZ).

Specialist supplier Hampshire Generators said it expected to start selling a 400W plug-in solar kit – one that does not need to be installed by an electrician – online from 27 August.

“I can’t see any problem with this registering process [with the ENA],” said managing director Andrew Williams. “It should be straightforward. Our devices are already ENA certified and on the register.”

“I’m assuming the big retailers will be ready to go with products at the end August. I think you’ll see them in supermarket aisles,” Williams added.

“The timing of it is a bit of shame in that so much of this summer has been missed. But people should be able to catch good weather at the end of August and in September.”

Another manufacturing source told The i Paper that they were “close” to having their products ready for sale with major retailers at the end of this month or very soon afterwards.

Final checks are being made to make sure registration with the ENA is in place. “We’re definitely close,” they said.

Lorna Wallace-Smith, head of UK communications for manufacturer EcoFlow, said the company had been “engaging” with the Government to make sure the compliance process was complete and “consumers have complete confidence”.

She added: “We’ll have more to share on our plans soon.”

Safety concerns

Self-install solar panels will be limited to 800W per household electricity circuit. They come with microinverters, which allow them to be plugged into three-pin sockets.

They automatically start generating some of the power for other devices in the circuit, such as kettles or fridges or washing machines.

Bodies such as the Electrical Contractors Association (ECA) and Institution of Engineering and Technology (IET) have raised safety concerns.

They have warned that plug-in solar panels could overload circuits – creating a risk of fire and electrical shocks – without careful checks by qualified electricians.

They argue that many older residual current devices (RCDs) in UK households are not set up for power-generating devices such as solar panels.

Mark Coles, head of technical regulations at IET, said he wanted the Government to make sure all manufacturers had carefully consulted the product specification and got their devices correctly verified with the ENA. “I sincerely hope things aren’t rushed,” said Coles. “We’re fully behind the technology, but the roll-out has to be safe.”

The engineering expert advised residents to consult an electrician to check if their RCD can cope with such devices.

However, DESNZ has said an independent electrical safety study had already concluded that self-install plug-in solar panels were safe, provided product standards were met.

Hopes of catching ‘some of the summer’

Retailers including Amazon, Lidl, Asda and B&Q attended a roundtable with Government in June to discuss stocking the panels.

B&Q, Asda and Lidl said they had no update on when they might be in stores.

John Boumphrey, Amazon’s UK and Ireland manager, said the coming sale of plug-in panels would be a “practical step” to cut bills and emissions, adding: “We’re looking forward to helping customers access this technology.”

Gareth Simkins, a spokesperson for industry body Solar Energy UK, said: “We hope they can be made available quite quickly after August 27 and catch some of the weather this summer.”

A DESNZ spokesperson added: “They are a transformative technology that can save people hundreds of pounds on their bills.”

Ministers do not anticipate landlords refusing to give tenants permission for plug-in solar, but will “consider” changes to the law if it becomes a “friction” point.