Labour’s plan to nationalise Britain’s energy network would make the country poorer, hinder efforts to tackle climate change, and threatens a return to the frequent power cuts of the past, the UK’s leading business lobby group has warned.

Jeremy Corbyn is expected to outline plans that would transfer companies including National Grid and the network arms of Scottish Power and SSE, to public ownership soon after a Labour election win.

The Labour leader, along with the party’s shadow business secretary, Rebecca Long-Bailey, is expected to say on Thursday that the UK’s£62bn energy infrastructure – the pipes and cables that supply homes and businesses with gas and electricity – would be taken back into state control at a price to be determined by parliament, according to The Guardian.

But the CBI said on Wednesday the proposals amounted to hanging a “closed” sign above the UK, with renationalisation delivering “a triple whammy neither citizens nor the country can afford”.

Companies including National Grid, the network arms of Scottish Power and SSE, as well as smaller regional grids, would all come under public ownership if Labour wins power. Current investors in those firms would be reimbursed with government bonds.