Following David Cameron’s outrageous comments at PMQs today, turning his back on green government, Oxford-based SERA activist Tom Hayes says the PM has abandoned his commitment to fighting climate change.

Today at Prime Minister’s Questions, David Cameron performed what surely ranks as one of the most screeching U-turns in modern political history. Under pressure from Ed Miliband on energy prices, he surprised observers by announcing his intention to cut heating bills by curtailing some of the flagship green initiatives he launched with fanfare three years ago. More concerned with reeling in disaffected Conservative MPs than with rolling back the tides, the PM jettisoned his commitment to fighting climate change without even pausing for breath.

At a time when people are still feeling a chill economic wind, cheap energy has to be a priority. Just last week Southern Electric charged Oxfordshire households an extra £104 a year for their energy, confirming what many of us have long suspected: that large fuel bills will soon be landing on our doormats. In our country, the seventh richest in the world, the between heating and eating is a pressing one, leading to fatal consequences. One report shows fuel poverty causing 10% of the 27,000 excess deaths happening each winter, and countless flu and related visits to doctors and hospitals. That’s why our party is promising to freeze costs and make the energy industry competitive – a move that will stop firms raising bills when wholesale prices go up and holding them at high levels when prices go down again.

Economic necessity is not an excuse for government to leave the playing field when it comes to our planet’s sustainability. A number of the Coalition’s recent moves suggest it believes the short-term growth that can boost its poll numbers before the next election will only come at the expense of sustainability. Cameron’s opposition to parliamentary calls for a decarbonisation target, followed by Osborne’s nods and winks in support of the expansion of fracking, pursued by the Environment Secretary Owen Paterson’s baseless cynicism about wind power could passably be soundtracked by the Benny Hill theme music.

Despite having the Energy brief over the last three years, the Lib Dems are nowhere on such matters. As the new nuclear announcement this week shows, DECC’s homepage may as well just be a photo of Ed Davey shrugging. By developing policy in this way, the Lib Dems and Tories are gearing investments back towards wasteful fuels and away from renewables. If it continues with this approach, Britain will abet disastrous global temperature rises and forfeit its hard-won reputation for environmental stewardship. But it will also have shot itself in the foot economically.

The Government is legally obligated to generate 15% of energy from renewable sources by 2020, and in December of last year it boasted around 30% of electricity generation would come from such sources by the end of the decade. But this June, statistics showed clean energy investment had slumped from £7.5bn in 2009 to £3.5bn in 2012. Loans to help buy equipment for big green energy projects had dropped off even more dramatically. This funding gap is a ticking time bomb, one that policymakers must defuse if we are to avoid a sharp spike in energy costs down the line.

Such a lack of investment also poses a dangerous threat to those who work in our renewable industry. In the South-East, there are over 100 wind and wave generators, 28 bio-energy sites and 12 hydro plants.  These energy-generating centres – and hundreds of others like them across the country – are not only vital to the future of our energy supply.  They represent the livelihoods of those who build, man and maintain them.

Without government subsidies to renewable and low carbon technologies, private investors are disappointedly crumpling their lists of potential investments. Investments promising significant leaps for the generation of clean energy and profit sadly look too costly or risky as long-term capital expenditures. Losing subsidies opens up a funding gap and an energy production fall which policymakers will end up regretting when energy costs sharply spike, power blackouts threaten, and our economy and living standards slump still further.

Nearly 25 years ago, a British politician stood before the United Nations and warned that while we needed wealth to protect the environment, economic growth must not “plunder the planet today and leave our children to deal with the consequences tomorrow”. Her name was Margaret Thatcher. When the noisiest Tory table-banger begins to sound a little more reasonable, it can only be because her children in government are behaving so recklessly today. When that happens, you know the Tory party’s in big trouble. And because the prosperity of the country, and especially its poorest people, is bound up with the state of the governing party, you know the country’s in really big trouble.

Tom Hayes is an Oxford Labour and Co-operative activist who has worked as an Energy and Climate Change adviser. He tweets at @tomhayes1983.