Doubts are growing about the future protection of the UK's environment following Brexit.
The Financial Times reported that an official paper shared by ministers proposed to deviate from green standards set by the European Union.
It said the UK was open to significant divergence - even though the Prime Minister has previously promised standards won't fall.
The government says it "doesn't recognise" the document - but the paper chimes with a BBC analysis which suggests the green watchdog planned after Brexit may be toothless.
At the moment Britain's standards on water, air, waste and wildlife are enforced by the EU.
So far, government ministers have had four chances to guarantee equal environmental standards after Brexit, but have declined the opportunity to follow through.
Their critics accuse them of creating the illusion of strong action without actually ensuring it will happen.
The Environment Bill - described by the Prime Minister as the "huge star of our legislative programme" - will be debated for the first time on Monday.
It aims to establish a new Office for Environmental Protection (OEP) to take on the job of ensuring ministers hit their own targets following Brexit.
But, critics warn this watchdog will not be truly independent because it will answer to the government, rather than to Parliament.
The suggestion is the government will not be able to issue the sort of fines previously instigated by the EU which have concentrated ministers' minds in recent years.
Mary Creagh, the Environmental Audit Committee chair, said: "The only reason the government have done anything on waste, landfill and air quality is because of the threat of EU fines."
Ministers argue that the watchdog would be able to take ministers to court.
They say it would be absurd for a regulator to actually fine the government, because it would simply transfer funds from one part of government to another.
Environmentalists want the government to face the threat of fines, with the proceeds going to green projects.
In addition, the critics say the 2037 date for enforcement of targets in the Environment Bill is far too late.
"This is completely unacceptable," said Ms Creagh. "We are in an environmental crisis - we need to act like it."
The Environmental Audit Committee wants the watchdog to be fully independent - similar to the National Audit Office, which reports to Parliament (not the government) and whose head is appointed by MPs.
Boris Johnson is under pressure from Brexiteer MPs to impose complete independence from EU environmental legislation after the UK leaves the EU.
A statement by the government said: "By setting long-term, legally-binding environmental targets the UK is showing global leadership at a crucial time for our planet.
"Given the scale of the challenges we face, our targets have to be ambitious and deliver sustainable results.
"We will need to give businesses and the public sufficient time to make the necessary changes to help us get there."
"The OEP will hold the government to account to make sure it is on track."
Environmentalists say there is much good in the bill - but they simply don't trust the government to deliver.
Not legally binding
Ministers have recently taken four different steps that might have included a legal commitment to non-regression.
These included the Withdrawal Agreement, the Withdrawal Agreement Bill, the Environment Bill and a set of 'assurances' provided to MP Caroline Flint.
But, none would actually bind the UK in law to maintaining high environmental standards which are comparable to those enforced by the EU.
This is a weaker position than adopted under Theresa May's rejected deal.
Critics say the government has a track record of missing environmental targets, with the number of serious pollution incidents recorded in 2018/19 rising to its highest level since 2014-15.
A leaked document from last year showed the government had actually abandoned agreed targets to conserve 50 per cent of England's sites of special scientific interest (SSSIs), by area, by 2020.
It is understood that The Department for Environment, Food and Rural Affairs' ambitions have been weakened by the Treasury and by Liz Truss at the trade department.
Ruth Chambers, from GreenerUK, said: "The bill includes several measures which could seriously undermine the water environment - and the biodiversity and nature clauses should be strengthened.
"It is silent on tackling the UK's global footprint.
"This must be addressed, else the UK risks undermining its global leadership credentials ahead of key international summits."
Follow Roger on Twitter @rharrabin