The government is facing growing pressure to stop non-essential construction work to help tackle the spread of coronavirus in the UK.
On Tuesday, Health Secretary Matt Hancock said those who cannot do their jobs from home should go to work to “keep the country running”.
Construction work can continue so long as people are 2m (6.5ft) apart, Mr Hancock said.
But critics said public health should be prioritised over the economy.
Former Tory cabinet minister Iain Duncan Smith joined those calling for a pause to non-essential work, telling BBC Two’s Newsnight: “I think the balance is where we should delete some of those construction workers from going to work and focus only on the emergency requirements.”
Andy Burnham, Labour Mayor of Greater Manchester, told the programme the decision to allow non-essential work appeared to have been made for “economic reasons”.
“When you’re in the middle of a global pandemic, health reasons alone really should be guiding all decision-making,” he said.
Boris Johnson, who faces Prime Minister’s Questions later, has so far resisted pressure from politicians, unions and workers themselves to halt construction work.
In Scotland, First Minister Nicola Sturgeon has said building sites should close, unless it involves an essential building such as a hospital.
On Tuesday, the number of coronavirus deaths in the UK rose to 422, according to the latest Department of Health figures, with more than 8,000 confirmed cases of the virus.
Some builders and construction workers have said they feel “angry and unprotected” going to work, while others are under pressure from employers to go in.
But speaking at the daily coronavirus briefing in Downing Street on Tuesday, Mr Hancock said construction workers – many of whom work outdoors – could and should continue to go to work as long as they are able to remain 2m apart at all times.
“The judgment we have made is that in work, in many instances, the 2m rule can be applied,” he said.