The government has a "ramshackle, Dad's Army" approach to coping with the impact of rising temperatures, its own climate advisers have warned.
The annual report reflects on how the government is performing in relation to its climate change targets - and comes just a month after Theresa May announced the United Kingdom would be the first G7 nation to legally bind itself to a net zero target.
Meanwhile, action to prepare homes, businesses and natural environment for a warming world is less ambitious than it was ten years ago.
In a separate, related report, the committee also found that the United Kingdom is seriously underprepared for protecting citizens from the impacts of climate change, saying that England is still not ready to face even a 2C rise in global temperature.
Baroness Brown of Cambridge, chair of the CCC's adaptation committee, said: "The UK is not ready for the impacts of climate change, even at the minimum expected level of global warming".
Government departments should adopt a net-zero carbon emissions policy and improve coordination of anti-climate change measures, an advisory panel has said, in a report calling on the government to demonstrate it is "serious" in its commitment to reaching net-zero emissions in the next 30 years.
Committee chairman Lord Deben said: "The whole thing is really run by the Government like a Dad's Army. We can't go on with this ramshackle system".
More action is needed to prevent overheating in homes, hospitals and schools as the risk of heatwaves rises, to tackle flash flooding from heavy downpours, cut water consumption and protect soils and wildlife habitats in England.
That's the verdict of a new 2019 Progress Report to Parliament from the Committee on Climate Change (CCC) - the Government's eco advisers - on reducing United Kingdom emissions.
He said that when they looked at the plans for dealing with climate change, there was a "tale of two governments".
The CCC, however, said the government has been too slow to develop technology to capture, store and use carbon dioxide emissions, held back the development of onshore wind farms, and failed to launch large-scale trials to use low-carbon hydrogen.
"Just last month the United Kingdom set a world-leading climate target but there is now a void between our ambition and policies to actually meet it". Over the past year, it says, the government has delivered just one of 25 critical policies needed to get emissions reductions back on track.
The CCC has repeated warnings that the government's current policies and climate change plans are insufficient to meet the UK's fourth and fifth carbon budgets, covering 2023-2027 and 2027-2032.
"Getting to net-zero requires will require action across all parts of government and our economy", she said.
"The effects of climate change are already being felt in the United Kingdom".
The only action requested by the CCC for 2018 that the government did deliver was to maintain a carbon tax on power emissions stations after Brexit.
"We know there is more to do and legislating for net zero will help to drive further action".
"We'll set out plans in the coming months to tackle emissions from aviation, heat, energy, agriculture and transport as well further measures to protect the environment from extreme weather including flood protection and nature restoration".