Government website states the following:
If you have symptoms of coronavirus (COVID-19), however mild, OR you have received a positive coronavirus (COVID-19) test result, the clear medical advice is to immediately self-isolate at home for at least 7 days from when your symptoms started. Do not go to a GP surgery, pharmacy or hospital. You should arrange to have a test to see if you have COVID-19
Following a positive test result, you will receive a request by text, email or phone to log into the NHS Test and Trace service website and provide information about recent close contacts
After 7 days, or longer, if you still have symptoms other than cough or loss of sense of smell/taste, you must continue to self-isolate until you feel better.
You do not need to self-isolate if you only have a cough or loss of sense of smell/taste after 7 days, as these symptoms can last for several weeks after the infection has gone.
If you live with others and you are the first in the household to have symptoms of coronavirus (COVID-19), then you must stay at home for at least 7 days. All other household members who remain well must stay at home and not leave the house for 14 days. The 14-day period starts from the day when the first person in the household became ill.
Staying at home for 14 days will greatly reduce the overall amount of infection that people in your household could pass on to others in the community.
If anyone else in the household starts displaying symptoms, they must stay at home for at least 7 days from when their symptoms appeared, regardless of what day they are on in their original 14-day isolation period.