Senior public health officials have made a last minute plea for ministers to scrap the easing of the lockdown tomorrow.
Officials have warned that the country is not prepared to deal with any surge in infection.
They also warned that public resolve to take steps to limit the transmission of COVID-19 has been eroded, the Guardian reports.
The Association of Directors of Public Health (ADPH) said new rules, including allowing groups of up to six people to meet outdoors and in private gardens, were 'not supported by the science'.
They said pictures of crowded beaches, parks and beauty spots over the weekend showed 'the public is not keeping to social distancing as it was'.
On Saturday and Sunday, outdoor spaces were packed as people anticipated the lifting of restrictions on what has been dubbed 'happy Monday'.
Schools will reopen, some non-essential retailers can trade, and up to six people can meet outside.
The most vulnerable people who have been 'shielding' can safely spend time outdoors, either with a member of their household or one other person.
But Jeanelle de Gruchy, president of ADPH, told the Guardian her colleagues across England were 'concerned' that the government is misjudging the balance of risk between more social interaction.
She said the lockdown restrictions are being eased 'too quickly' and has called on ministers to postpone the easing until more is known about the infection rate, the test and trace system is better established and public resolve to maintain physical distancing and hygiene can be reinforced.
Speaking at the daily Downing Street press conference on Sunday, Robert Jenrick said that 'room for manoeuvre' is quite limited.
But the Secretary of State for Housing, Communities and Local Government said the government are confident that the steps they have taken are manageable.
The public health directors at ADPH, who work for local authorities, warned that the country is 'at a critical moment'.
They said the government's NHS Test and Trace system is far from being the robust operation that is now urgently required as a safeguard to easing restrictions'.
They also warned that the 'R' infection rate - estimated to be between 0.7 and 0.9 – was too close to 1.
Officials also said that the lockdown must remain in place until 'relentless efforts are made to regain and rebuild public confidence and trust following recent events' in an apparent reference to the Dominic Cummings affair.
