By Kylie MacLellan
LONDON (Reuters) - British Prime Minister Boris Johnson urged people on Sunday to "stay alert" to coronavirus risks, as he prepared to outline plans for gradually easing lockdown measures that have shuttered much of the economy for nearly seven weeks.
The government's decision to replace its flagship "stay at home" slogan drew criticism from opposition parties who argued that "stay alert" is too ambiguous.
Johnson, due to make a televised address at 1800 GMT, is expected to announce a limited easing of restrictions, such as encouraging those who cannot work from home to return to their offices and factories.
"Everyone has a role to play in helping to control the virus by staying alert and following the rules. This is how we can continue to save lives as we start to recover from coronavirus," Johnson said in a Twitter message.
He also tweeted a new government poster that lists rules including "stay at home as much as possible", "limit contact with other people" and "keep your distance if you go out".
Johnson will detail a system ranging from "green" at level 1 to "red" at level 5 that will allow the government to flag coronavirus risks in different parts of England and to increase restrictions where necessary.
The government wants the United Kingdom's other constituent nations - Wales, Scotland and Northern Ireland - to follow the same steps but they have the power to diverge in their measures.
Scottish First Minister Nicola Sturgeon said the only change she was making to lockdown measures was to allow people to exercise more than once a day.
"(That) is the only change that the Scottish government judges that it is safe to make right now without risking a rapid resurgence of the virus," she told a news conference.
Sturgeon added she was sticking with the "stay at home" message and had asked the UK government not to use its "stay alert" advertising campaign in Scotland.
Housing minister Robert Jenrick told BBC TV Johnson would not announce a "grand reopening" but would set out a roadmap for the "weeks and months ahead".
"We need to have a broader message because we want to slowly and cautiously restart the economy and the country," he said in a separate interview with Sky News.
Britain has reported 31,587 deaths from COVID-19, the respiratory disease caused by the coronavirus, the second-highest death toll in the world after the United States, and some 215,260 confirmed infections.
The government has faced steady questions from the opposition Labour Party and others on why the country was not locked down earlier, why it has struggled to administer tests for the virus on a large scale and why there have been shortages of protective equipment for medics and care workers.
The Sunday Times reported that scientific advisers had told the government that deaths could exceed 100,000 by the end of the year if lockdown measures are relaxed too fast.
Jenrick said the country as a whole is currently at 4 on the new scale and authorities want that brought down to 3 as fast as possible.
"At each stage ... we will be in a position to open up and restart more aspects of the economy and of our lives," he said, adding that changes would be conditional on keeping the virus under control.
Colour-coded systems to distinguish regions with more or less risk have been used in other countries as they emerge from lockdowns, including France and India.
Opposition parties criticised the government's new "stay alert" slogan as confusing.
"There is no room for nuance," Labour health spokesman Jonathan Ashworth told BBC TV.
"Many people will be puzzled by it ... This virus really does exploit ambivalence and thrive on ambiguity, we need clarity at all times."
(Reporting by Kylie MacLellan; Editing by Catherine Evans and Frances Kerry)