The mayor of London was responding to a Department of Energy and Climate Change consultation on the proposed 87 per cent cut to feed-in tariffs.

In a letter to energy minister Andrea Leadsom, deputy mayor for environment and energy Matthew Pencharz wrote that the reductions in FiTs should be phased “over a two-three year period”.

He wrote: “The mayor believes that the solar PV industry needs some certainty over the next few years as it transitions to a subsidy-free and long-term sustainable future.”

Mr Pencharz, writing on behalf of Mr Johnson, continued: “Unfortunately the current proposals, which have been consulted on, with little or no prior warning, to come into force in the new year has (sic) created great uncertainty in the solar PV industry, potentially putting at threat thousands of jobs across the UK.

“The mayor is concerned about the potential impact on the 3,100 jobs, mainly in SMEs, which make up the solar PV industry in London.”

He added that phasing in the cuts “would provide a clear pathway” for the industry, “reducing the impact of business and job losses”.

Earlier this week, Ms Leadsom told a committee of MPs that she was “open-minded” over the consultation, which closes today (Friday 23 October).

A number of solar installation firms have gone into forced being closed or sell off parts of their business after the government’s plans were announced, with experts claiming that thousands of jobs could be lost across the industry.

Sustainable Homes managing director Andrew Eagles said the changes, along with other government policies affecting the renewables sector, had created “a perfect storm”, that could affect “tens of thousands of jobs”.