Ministers are under fire after revealing their strategy to achieve net-zero carbon emissions by 2050 will not be released until the end of the year.

It means the plans – which will require huge and potentially unpopular changes to transport, energy and agriculture – will only emerge more than a year after the legal commitment was made.

“If this is true, it doesn’t really smack of a government treating this issue as a climate emergency,” said Clive Lewis, Labour’s Treasury spokesman and a leadership candidate.

And Wera Hobhouse, the Liberal Democrat climate emergency spokesperson, pointing to the wildfire crisis in Australia, said: “While the world is waking up to the dangers of climate change, this Tory government is still on holiday.

“Without a proper plan of how to get to net zero, the Conservative’s pledges are empty.”

The government had already been fiercely criticised for lacking urgency and practical solutions for tackling the climate emergency, in announcements so far.

The climate crisis was barely mentioned by Boris Johnson during the election campaign and he boycotted the Channel 4 debate on the issue – when he was replaced by a melting ice sculpture.

Previously, ministers had suggested a roadmap to net zero would be published “during” 2020, with the March budget seen as a possible date for taking tough decisions.

But, speaking in the Commons – while claiming the UK was a “world leader” in reducing emissions – Treasury minister Simon Clarke said a review would take until “this autumn”.

Climate change: Decade's defining issue in pictures Show all 20 1 /20 Climate change: Decade's defining issue in pictures Climate change: Decade's defining issue in pictures California In this decade, humans have become ever more aware of climate change. Calls for leaders to act echo around the globe as the signs of a changing climate become ever more difficult to ignore Getty Climate change: Decade's defining issue in pictures Athens, Greece Fierce wildfires have flared up in numerous countries. The damage being caused is unprecedented: 103 people were killed in wildfires last year in California, one of the places best prepared, best equipped to fight such blazes in the world AFP/Getty Climate change: Decade's defining issue in pictures Redding, California Entire towns have been razed. The towns of Redding and Paradise in California were all but eliminated in the 2018 season AP Climate change: Decade's defining issue in pictures Athens, Greece While wildfires in Greece (pictured), Australia, Indonesia and many other countries have wrought chaos to infrastructure, economies and cost lives AFP/Getty Climate change: Decade's defining issue in pictures Carlisle, England In Britain, flooding has become commonplace. Extreme downpours in Carlisle in the winter of 2015 saw the previous record flood level being eclipsed by two feet AFP/Getty Climate change: Decade's defining issue in pictures Hebden Bridge, England Hebden Bridge in West Yorkshire has flooded repeatedly in the past decade, with the worst coming on Christmas Day 2015. Toby Smith of Climate Visuals, an organisation focused on improving how climate change is depicted in the media, says: "Extreme weather and flooding, has and will become more frequent due to climate change. An increase in the severity and distribution of press images, reports and media coverage across the nation has localised the issue. It has raised our emotions, perception and personalised the effects and hazards of climate change." Getty Climate change: Decade's defining issue in pictures Somerset, England Out west in Somerset, floods in 2013 led to entire villages being cut off and isolated for weeks Getty Climate change: Decade's defining issue in pictures Dumfries, Scotland "In summer 2012, intense rain flooded over 8000 properties. In 2013, storms and coastal surges combined catastrophically with elevated sea levels whilst December 2015, was the wettest month ever recorded. Major flooding events continued through the decade with the UK government declaring flooding as one of the nation's major threats in 2017," says Mr Smith of Climate Visuals Getty Climate change: Decade's defining issue in pictures London, England Weather has been more extreme in Britain in recent years. The 'Beast from the East' which arrived in February 2018 brought extraordinarily cold temperatures and high snowfall. Central London (pictured), where the city bustle tends to mean that snow doesn't even settle, was covered in inches of snow for day PA Climate change: Decade's defining issue in pictures London, England Months after the cold snap, a heatwave struck Britain, rendering the normally plush green of England's parks in Summer a parched brown for weeks AFP/Getty Climate change: Decade's defining issue in pictures New South Wales, Australia Worsening droughts in many countries have been disastrous for crop yields and have threatened livestock. In Australia, where a brutal drought persisted for months last year, farmers have suffered from mental health problems because of the threat to their livelihood Reuters Climate change: Decade's defining issue in pictures Tonle Sap, Cambodia Even dedicated climate skeptic Jeremy Clarkson has come to recognise the threat of climate change after visiting the Tonle Sap lake system in Cambodia. Over a million people rely on the water of Tonle Sap for work and sustinence but, as Mr Clarkson witnessed, a drought has severley depleted the water level Carlo Frem/Amazon Climate change: Decade's defining issue in pictures Addis Ababa, Ethiopia In reaction to these harbingers of climate obliteration, some humans have taken measures to counter the impending disaster. Ethiopia recently planted a reported 350 million trees in a single day AFP/Getty Climate change: Decade's defining issue in pictures Morocco Morocco has undertaken the most ambitious solar power scheme in the world, recently completing a solar plant the size of San Francisco AFP/Getty Climate change: Decade's defining issue in pictures London, England Electric cars are taking off as a viable alternative to fossil fuel burning vehicles and major cities across the world are adding charging points to accomodate AFP/Getty Climate change: Decade's defining issue in pictures Purmerend, The Netherlands Cities around the world are embracing cycling too, as a clean (and healthy) mode of transport. The Netherlands continues to lead the way with bikes far outnumbering people Jeroen Much/Andras Schuh Climate change: Decade's defining issue in pictures Xiamen, China Cycling infrastructure is taking over cities the world over, in the hope of reducing society's dependency on polluting vehicles Ma Weiwei Climate change: Decade's defining issue in pictures Chennai, India Despite positive steps being taken, humans continue to have a wildly adverse effect on the climate. There have been numerous major oil spills this decade, the most notable being the BP oil spill in the Gulf of Mexico in 2010 AFP/Getty Climate change: Decade's defining issue in pictures Amazon rainforest, Brazil More recently, large swathes of the Amazon rainforest were set alight by people to clear land for agriculture AFP/Getty Climate change: Decade's defining issue in pictures California This decade may have seen horrors but it has led to an understanding that the next decade must see change if human life is to continue Getty

It also puts the announcement slap up against the crucial United Nations climate change summit taking place in Glasgow in mid-November, which will put the UK in the international spotlight.

Ms Hobhouse added: “The UK has the opportunity to lead the world with meaningful action. Instead we have dither and delay with what looks like no time for MPs to scrutinise government plans before the [climate change conference].”

Last April, the government’s independent advisers recommended the target to end the UK’s contribution to climate change by 2050, the toughest of the major economies.

And it set out the likely necessary measures, including an earlier ban on petrol and diesel cars, an end to gas boilers, huge investment in green energy, or sharp curbs to meat-eating.

Theresa May then won the plaudits for pushing through the legal duty to end net emissions by the middle of the century – but left the action plan to her successor.

During Treasury questions, Mr Clarke, the exchequer secretary, said Mr Johnson had set up a new cabinet committee on climate change because it “takes its responsibilities very seriously”.

He then said: “Later this year, the government will be setting out further plans to reduce emissions in key sectors such as transport, energy and buildings while seizing the economic benefits of clean growth.

“We have launched a review into the transition into a net zero economy, how that will be funded, and that review will publish its findings this autumn.”