An alliance of 100 organisations has written to Prime Minister David Cameron urging him to support small-scale renewables ahead of the comprehensive feed-in tariff review.

Details of the review, expected to be released within the next fortnight, could see the feed-in tariff significantly cut as the Department for Energy and Climate Change continues its attempts to rein in spending under the Levy Control Framework which was revealed in July to be facing a £1.5 billion overspend by 2020/21.

In the letter, the organisations state that they have been “surprised and concerned” by various cuts to green energy programmes and reference the “great concern” caused by the imminent feed-in tariff (FiT) review.

“Stable support provided through FiTs has been key to the sharp cost reductions delivered by British renewables and has put the prospect of zero subsidy within reach. Maintaining a strong FiT scheme offers excellent value for money; analysis shows that continued ambitious deployment of renewables under FiTs will have a very modest future impact on household bills.

“[Subsidy-free renewables] would be an enormous prize – unleashing unprecedented competition and technological innovation for the benefit of consumers, communities, our health and the environment, and lowering consumer bills for hard working families. Yet this cost reduction can only happen through the maintenance of stable and effective policies,” the letter read.

Organisations co-signing the letter include various trade associations, councils, developers and global retailers such as IKEA. Leo Murray, director of strategy at campaign group 10:10, said the timing of the review could not have been worse.

“The UK will not be taken seriously at December’s UN climate talks in Paris if it has done nothing but undermine confidence in our national decarbonisation plans for the last six months. Maintaining strong growth in local renewables through the FiT would be a clear signal that David Cameron is still serious about tackling climate change,” he added.

Leonie Greene, head of external affairs at the STA, said: “We are looking to the Prime Minister to take control of energy policy after a summer of hugely damaging policy decisions. There was nothing in his manifesto about rolling back solar power which government’s own polling shows is supported by over 80% of the British public.”

The letter will ratchet up pressure on the Conservative government and is the latest sign of increased unity within the renewables industry in the face of damaging policy decisions. Last week seven trade associations collaborated on a response to the planned cancellation of pre-accreditation, informing energy secretary Amber Rudd of their discontent at the move.