He confirmed on Tuesday that all workers and their families will be offered tests as testing capacity in the UK is ramped up to 73,000 per day.

Forty-one drive through testing centres are now in operation with a further 48 due to come on stream this week. A further 70 mobile testing stations largely operated by the army are also due to be operating by the end of the week.

Hancock said: “We now have the capacity to make testing available to all workers who have to leave home to go to work and members of their households who have symptoms.”

He had come under pressure from construction union Unite to extend testing to construction workers because so many had kept working through the lockdown.

Unite assistant general secretary Gail Cartmail said: “Unite is pleased that the government has supported our call to ensure that construction workers who continue to work can easily access testing for COVID-19.

“This will significantly help prevent the spread of the virus on construction sites.

“Testing alone however will not stop the spread of this deadly disease. It is imperative that construction workers are able to continually socially distance from when they leave home in the morning to when they return at night.

“The dangerous PHE guidance must be withdrawn and the Health and Safety Executive must step up to the plate and insist on procedures that require workers to social distance on sites at all times to reduce risks of infection.”

It is hoped testing will help to provide evidence whether safe site working practices are preventing the spread of coronavirus on site.