Mayor of London warns that thousands of jobs are being put at risk, in letter sent to the energy minister on final day of government consultations on the proposals

Boris Johnson has waded into the growing row over the solar industry by calling on the energy minister, Andrea Leadsom, to halt plans to cut subsidies to the industry by 87% from January.

One the last day of a consultation period into the proposed aid reductions, Johnson accused the government of acting with “little or no prior notice”, endangering thousands more solar industry jobs.

“The Mayor believes that the solar PV industry needs some certainty over the next few years as it transitions to a subsidy-free and longterm sustainable future,” said Matthew Pencharz, deputy mayor for the environment and energy, in a letter to Leadsom released on Friday.

“The current proposals, which have been consulted on, with little or no prior warning, to come into force in the new year have created great uncertainty in the solar PV industry, potentially putting at threat thousands of jobs across the UK,” he added.

The intervention came as a revolutionary solar scheme to produce energy from the roof of the Tate Modern was launched, and yet could be could be the last of its kind, according to its developer Solarcentury.

The £1m project – made even more special by the fact that the Bankside site on the Thames was until 1981 used to house an oil-fired power station – was officially opened just as government wound up a consultation that industry says could kill off solar.

Frans van den Heuvel, the chief executive of Solarcentury, said it had paid for the Tate installation with its own money to show its commitment both to art and to highlight the benefits of renewable energy.

But new projects were already falling away and jobs being axed because of government proposals to slash rooftop solar subsidies by 87% on top of previous aid reductions for the industry.

“In housing programmes alone, we’ve [Solarcentury] already had £16m of confirmed business cancelled, which equates to approximately 6,500 homes that won’t benefit from solar panels,” he argued.

“And this is just a small part of a much larger pipeline of business that won’t happen if the [subsidy] cuts go ahead as planned,” added Heuvel who estimated over 100 subcontractor jobs were lost on his schemes, adding to the 1,000-plus cut by other companies.

The Solar Trade Association used the Tate event to warn, once again, that 27,000 jobs were under threat from the government proposals which would come into effect from January next year.

The solar lobby group argues that one more slug of government funding, paid for as usual through customer bills, would enable the industry to become self-sufficient by the end of the decade.

Ben Warren, a partner at major business services firm, EY, said it was very surprising that ministers were willing to give major subsidies to the nuclear industry for the Hinkley Point C plant in Somerset over 35 years and yet go “cold turkey” on solar.