In the UK Construction industry, the advice right now is that the 2M rule is not sacrosanct. However it should be "broken" with care, caution and common sense. Advice handed down is to work side by side, not facing one another. Keep close proximity working to periods of 15 mins if possible. Keep gangs/travelling companions to the same people to reduce cross infection, Where passing in a narrow space, turn faces away, in a moving vehicle keep the windows and vents open. Above all wash hands and sanitise frequently and thoroughly and observe 2M where possible.
I am not saying if it's good or bad practise or how effective it will be at reducing transmissions; but as Radgirl says, the economics have to overtake the health measures at some point and HM Government has constantly made it clear that if you cannot work from home, you continue to work as near normally as possible.