South Devon MP Caroline Voaden has expressed “deep disappointment” after the climate and nature bill last week failed to pass its second reading in the House amid accusations the government is rowing back on its net zero commitment.

The proposed law, which would have set legally binding targets for climate and nature, fell at the first hurdle when the government won a motion to end debating the bill, which was introduced by Liberal Democrat MP, Roz Savage.

Among the bill’s proposals were legally binding targets to reverse biodiversity loss, and the creation of citizen assemblies to produce climate-and-nature-friendly recommendations for MPs to consider.

The bill would have also required annual targets to reduce CO2 emissions.

Government ministers reportedly insisted on the removal of the clauses that would have required the UK to meet agreed targets at international climate summits.

Although the next scheduled reading has been postponed until July, it is thought the bill is effectively dead as it will not get more parliamentary time.

Ms Voaden said: “We’re in the last chance saloon as far as fighting the climate crisis goes. What I want to see from our government is ambition and boldness – I’m not seeing any of that from Labour.

“They talk about growth, but seem to ignore the fact that the cost of not taking the bold action we need will be far, far higher than the cost of making the changes we urgently need. And as the effects of the climate crisis spread and deepen, economies will shrink and possibly even collapse – so there is an economic as well as a moral and human imperative to do this.”

She accused the prime minister of turning his back on net zero, a view shared by TV chef and environmental campaigner Hugh Fearnley-Whittingstall, who ominously said ahead of the vote that there were “really worrying noises” the government was rowing back on its support for the bill.

The vote marks a perceived shift in attitude from the government about its environmental credentials.

It is believed Labour will soon announce the expansion of Heathrow’s third runway, while Sir Keir Starmer has made it clear the government will block “excessive” legal challenges to major infrastructure projects.

Opponents have criticised the bill on the grounds that it would ban the extraction and importation of fossil fuels, claiming it would have a negative impact on energy independence and cause bills to soar (earlier this month, there were reports that Britain’s gas storage levels were alarmingly low).

Critics were also against moves that would have reputedly prioritised rewilding projects over housing and agriculture. The role of unelected citizen assemblies was heavily criticised as well (the bill mentioned assemblies to “advise” the secretary of state in drafting strategy).

Conservative MP Andrew Bowie said the bill would result in “the highest electricity prices in the world” and cause job losses.

But Ms Savage, who was quoted by the BBC, said: “There are laws of humans and there are laws of nature. Whether or not the bill makes it into human law, for sure the laws of nature will ultimately prevail.”