Boris Johnson has said the UK government will “advance with maximum caution” in considering any lifting of coronavirus restrictions, as Scotland formally extended its lockdown.
It comes as the Welsh government said media reports speculating how the PM might ease restrictions risked sending “mixed messaging” to the public.
Some newspapers suggested the rules on exercise could be relaxed and more people encouraged to return to work.
The PM will announce plans on Sunday.
By law, the government must review the restrictions every three weeks, and Thursday marks the latest deadline.
Mr Johnson will address the nation at 19:00 BST on Sunday to outline plans for England for the next stage of the lockdown, which was announced on 23 March.
Although the lockdown will largely stay in place, the “stay at home” message is expected to be scrapped.
With ministers keen to restart the economy, Mr Johnson has suggested some measures could start being eased on Monday.
Scotland, Wales and Northern Ireland have the power to diverge from what the government at Westminster decides on the lockdown – and could lift restrictions at a different rate.
Mr Johnson told a meeting of his cabinet earlier that the UK government would not do anything that risked a second peak, and would be guided “at every step” by the science and data.
The prime minister said the government would closely track the impact of any easing of the social distancing measures, and would not hesitate to tighten the rules if required, according to No 10.
The prime minister’s spokesman said we were at a “critical moment” in the fight against the virus, and the government would not do anything that “risks throwing away the efforts and sacrifices of the British public”.
No 10 said there would be a call with the leaders of the devolved nations later.
At her daily briefing on Thursday, First Minister Nicola Sturgeon confirmed the lockdown would continue in Scotland, saying any easing of restrictions would be “very, very risky” at this stage.
The Scottish government has already set out a number of options for lifting the lockdown, but Ms Sturgeon said she would “not be pressurised” into easing measures prematurely.
She said her preference would be for all four nations to make changes together at the same pace but “we can decide in an entirely grown-up way if we are at different stages and want to go different ways”.
Ms Sturgeon added that media reports about the prime minister planning to ease the lockdown had not been discussed with the Scottish government.
Meanwhile, a Welsh government spokesman said it was “crucially important” people in Wales were “informed clearly and accurately” about any changes to the current restrictions.
“Some of the reporting in today’s newspapers is confusing and risks sending mixed messages to people across the UK,” he added.
The Northern Ireland Executive met on Thursday to discuss how and when to relax lockdown restrictions. First Minister Arlene Foster previously suggested Northern Ireland’s restrictions could be lifted at a different pace to the rest of the UK.
Any changes to the guidelines next week are expected to be very limited.
But BBC political editor Laura Kuenssberg said the government’s “stay at home” message – which it has pushed since the lockdown began – is “on the way out”.
Public Health England said it was “reviewing all communications materials in anticipation of moving to the next phase of the government campaign”.
Labour leader Sir Keir Starmer said he expected the government to continue with lockdown measures, and his party would support this.
“Lockdown needs to stay in place until we are sure the infection rate has gone down,” he told BBC Good Morning Scotland.
Acting Lib Dem leader Ed Davey said if the government’s message changed it was important there was an effective plan in place on testing and tracing contacts of those who were found to have the virus.
“We don’t want to give a false impression that things have changed dramatically and life can go back to normal – and it’s essential the government gets the balance right,” he told BBC Breakfast.