The PM says the government will proceed with “maximum caution” when considering easing coronavirus restrictions, as Scotland extended its lockdown.
It comes as the Welsh government described media reports speculating how Boris Johnson might ease lockdown measures as “confusing”.
Some newspapers suggested the rules on exercise could be relaxed and more people encouraged to return to work.
Mr Johnson will announce lockdown plans for England on Sunday at 19:00 BST.
By law, the government must review the restrictions every three weeks, and Thursday marks the latest deadline.
Although the lockdown – first announced on 23 March – will largely stay in place, the “stay at home” message is expected to be scrapped and it is likely more outdoor activities will be permitted.
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.
Downing Street said the prime minister wanted to maintain the “four-nation approach” to coronavirus measures, saying “the only circumstances where there should be divergence is when there is evidence that supports it”.
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.
Mr Johnson is due to speak with the leaders of the devolved nations later.
In Scotland, First Minister Nicola Sturgeon warned it could be “catastrophic” to drop the stay at home message as she announced that the nation’s lockdown was to be extended. She added that any easing of restrictions would be “very, very risky” at this stage.
However, Ms Sturgeon said the Scottish government may be prepared to allow people to spend more time outdoors.
Scotland 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.
Why could exercise rules be relaxed?
By Lauren Moss, Health Correspondent
Coronavirus does not discriminate – whether it’s indoors or outdoors, or if the weather is hot, cold or humid. As the World Health Organization points out, it can be transmitted in all areas.
The science indicates that the virus is transmitted through tiny respiratory particles when someone infected coughs or sneezes.
Some of these larger droplets fall to the ground, although there’s varying evidence of how far they can spread first.
The smaller specks sometimes hover in the air and then land on surfaces where they may remain for several days. We catch the virus when we touch those surfaces and then touch our eyes, mouth or nose.
That’s why the message to wash hands thoroughly and regularly hasn’t gone away since lockdown – it’s still just as important.
But when we are outside we are probably less likely to touch an infected surface and there’s more fresh air to dilute any particles. If we are allowed to spend more time outside, it will still be crucial to keep our distance from each other.
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”.
The prime minister has told opposition leaders he will deliver a statement in the House of Commons on the government’s next steps on Monday.
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.
It comes as the UK became the first country in Europe to record more than 30,000 people dying with coronavirus. The UK now has the second-highest number of recorded coronavirus deaths in the world, behind the United States.
However, ministers have argued it is too early to make full international comparisons.
On Thursday, a further 383 deaths were announced in England, along with 59 more in Scotland and 18 more in Wales.
The latest UK-wide figures and those for Northern Ireland will be published later.
In other developments:
- The Bank of England has warned that the pandemic will push the UK economy towards its deepest recession on record
- Black men and women are nearly twice as likely to die with coronavirus as white people in England and Wales, according to the Office for National Statistics
- Schools in Wales will not re-open on 1 June after closing due to the pandemic
- The UK has said 400,000 surgical gowns ordered from Turkey do not meet British safety standards
- Notting Hill Carnival has been cancelled, with organisers saying this was “the only safe option” amid the pandemic
- People have been warned to avoid beauty spots this bank holiday weekend, as temperatures are predicted to soar across England
- British Airways owner IAG has said it is planning for a “meaningful return” of flights in July at the earliest if lockdown measures are relaxed
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