Is there any duty on employers to close their workplace if a risk of contact with coronavirus is identified?

Current government guidance is that there is no need to close the workplace if someone suspected to have coronavirus (COVID-19) has been to the premises. Even if the person subsequently tests positive for coronavirus, closure of the workplace will not necessarily be recommended. The relevant public health body (eg Public Health England if the employer is in England) will advise the employer on what action to take in these circumstances.