England faces the prospect of enduring a longer full lockdown than other parts of the UK, as ministers continue to resist growing pressure to end their silence on the options for easing restrictions.

With Boris Johnson still away from work, business and trade union leaders joined opposition politicians in calling for openness about which measures might be relaxed first, to give them proper time to prepare.

But No 10 brushed off proposals from Scotland and Wales that are likely to see those nations soften their lockdowns first – instead acknowledging the growing likelihood that the united pan-UK approach will “fracture”.

It dismissed Wales’s idea of a “traffic light” system for unravelling restrictions – allowing some to be lifted as early as 7 May – saying the government “did not recognise” such a plan.

In contrast, England’s lockdown is likely to remain in its current form after 7 May, as the 18,000 community infection-chasers – seen as key to keeping down case numbers – will not be recruited and trained for many weeks.

The prime minister’s spokesperson admitted the four UK capitals moving in lockstep had only held “so far”. Asked if it would “fracture”, he did not deny the prospect, replying: “It hasn’t to this point.”

He refused to discuss options set out by the Scottish government to restore life to a “semblance of normality” over the coming months, as Nicola Sturgeon put it.

They include some pupils returning before others, redesigning classrooms to keep children 2m apart, allowing more businesses to reopen if they can guarantee social distancing, or even gatherings of up to 10 people.

Insisting London would not be rushed, the spokesperson said: “Once we are in a position where we want to set out more detail about some of the measures we will take we will do so.”

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Earlier, Mark Drakeford, Wales’s first minister, pointed to an early partial lifting, saying: “I hope we will be in a position to do that at the end of the current three-week lockdown period [on 7 May].”

Likewise, Arlene Foster, the first minister of Northern Ireland said: “We may decide, as a United Kingdom, on criteria which will mean that different regions will move at different times.”

The British Retail Consortium called for a strategy to be “communicated as early as possible”, while shopworkers said they feared being “caught on the hop” without time for protections to be put in place.

For Labour, Nick Thomas-Symonds, the shadow home secretary, urged ministers to start “a real public debate, looking at the public health options, looking at the economic impact”.

“The government needs to be open about its approach to the different options for easing the lockdown, to be transparent about how the different options are going to be considered and how they are going to be evaluated,” he said.

“This is so important because the British public are making great sacrifices every day and deserve a government that is open about its future plans.”

Cabinet members have so far refused to reveal any roadmap for Britain’s exit from lockdown, drawing criticism for repeatedly insisting any changes would be led by “the science”.

Ministers are also awaiting a detailed Office for National Statistics survey into rates of infection, and possible antibody immunity, which is not expected until at least early May.

Usdaw, the shopworkers’ union, said it expected more shops would open in the first phase of easing restrictions – but that would require work to install protective screens, put down markings and perhaps arrange stewarding to keep people apart.

“The government needs to be open and honest with the public, but I think there has been a mismatch of information so far,” Paddy Lillis, its general secretary, told The Independent.

“What is the message? If it is moving to opening non-essential shops, then the preparations need to be put in place now so we are not caught on the hop and everyone is clear about what needs to be done.”

Helen Dickinson, the BRC’s chief executive, praised the government’s actions so far, but added: “It is vital that this dialogue is maintained and that the exit strategy is communicated as early as possible, to give retailers time to address all practicalities and prepare their supply chains.”

Some experts have criticised the government for hiding behind the phrase “following the science”, as a cover for failing to make what are, in reality, political decisions.