For patients or employers requesting a fit note for periods of absence relating to Coronavirus, the Government states that a fit note can only be issued when a patient has had more than 7 consecutive days off sick due to an illness.
In the current situation some employees may need to quarantine at home even though they do not have symptoms, for example if another household member has symptoms, being high risk, or having concerns about the ability to work safely while maintaining social distancing guidelines, in these cases your GP CAN NOT issue a fit note as the time off work is not due to an illness and is not affecting your ability to work, but is a precaution to avoid transmitting or contracting Coronavirus.
GPs have a responsibility to prioritise the needs of patients who are clinically unwell. Isolation notes can be obtained from Isolation Note
Further information about Coronavirus and the work place can be found here Working safely during Coronavirus guidance