The move comes a day after Ernst and Young reported that the UK had crashed out of the top ten of its renewable energy country attractiveness index for the first time.
Earlier, Hilary Benn, the Shadow Foreign Minister called for the government to change course saying: "The very significant cuts being proposed by the current Government are likely to cost jobs and investment in the green economy", while Boris Johnson declared that he is "very concerned" by the changes.
Friends of the Earth renewable energy campaigner Alasdair Cameron said: "The government's attacks on solar power could cost more than 20,000 jobs and billions in investment, and risk the UK falling far behind other nations in developing crucial technologies.
"For the first time in centuries the UK is no longer at the forefront of developing new energy technology and infrastructure, and government policy is responsible.
"The Treasury must urgently listen to those investors, entrepreneurs and MPs who recognise the strategic importance of renewable technologies like solar power, and it must work to support the industry, rather than destroy it."
The solar industry's trade organisation welcomed growing call for Government to reconsider 'extreme' Feed-In Tariff proposals.
The STA joined a number of the powerful organisations calling on the Government to reconsider their FIT proposals after consultation with the industry and stakeholders.
The STA point out that the joint statement comes on the day that the CEO of Shell told Radio 4 today that solar would dominate energy generation in the future.
Leonie Greene, Head of External Affairs at the Solar Trade Association said: "The Government's proposals for British solar are extreme and they are damaging for both the industry and for consumers. Solar puts people and communities in control and the Government should back that - not take power from the people. It doesn't have to be like this, so we are reassured that so many organisations, from all walks of life, are joining our call for a rethink."
Energy Secretary Amber Rudd faced widespread criticism in the Commons today from MPs from all parties, as MPs described the jobs at risk in their communities.
The STA point out that the Government's own Impact Analysis (see link at bottom) shows their proposals will reduce the UK solar industry to a shadow of its former self, with insufficient business to sustain solar installers and the wider UK supply chain.
STA modelling, which has been verified by experts from Imperial College, shows that it will add only £1.70 to household bills in 2020 to deliver well over a million more solar homes. The modelling showed that it is growth and political stability which will drive the sector off subsidy through economies of scale. DECC's proposals are the complete opposite.
Leonie Greene said: "It is quite wrong to suggest we cannot afford to go solar. The truth is we cannot afford not to. It's hard to think of a greater waste of public money than building up a strong British solar industry, hailed by the Prime Minister as a success, and then pushing it over a cliff before it is ready to fly."
• The joint statement and the signatories can be seen here: www.foe.co.uk
• UK dropping out of the top 10 of the Ernst and Young renewable energy country attractiveness index can be seen here: www.ey.com
• Hilary Benn MP's concerns over cuts to solar power support can be seen here: www.hilarybennmp.com
• Boris Johnson's response to these cuts can be seen here: www.solarpowerportal.co.uk
• Government analysis of impact of Feed in Tariff review www.gov.uk