Crikey. We’re 11 months into this and people still aren’t clear. It’s very clear on the phe website.
If you live in the same household as someone with COVID-19
Stay at home and self-isolate. Do not go to work, school, or public areas and do not use public transport or taxis.
Your isolation period includes the day the first person in your household’s symptoms started (or the day their test was taken if they did not have symptoms) and the next 10 full days. This means that if, for example, your 10 day isolation period starts on the 15th of the month, your isolation period ends at 23:59 hrs on the 25th and you can return to your normal routine.
If you do not have symptoms of COVID-19 yourself, you do not need a test. Only arrange a test if you develop COVID-19 symptoms or if you are asked to do so as part of a testing programme for people without symptoms. If for any reason you have a negative test result during your 10 day isolation period, you must continue to self-isolate. Even if you don’t have symptoms, you could still pass the infection on to others. Stay at home for the full 10 days to avoid putting others at risk.
If you develop symptoms while you are isolating, arrange to have a COVID-19 PCR test. If your test result is positive, follow the advice for people with COVID-19 to stay at home and start a further full 10 day isolation period. This begins when your symptoms started, regardless of where you are in your original 10 day isolation period. This means that your total isolation period will be longer than 10 days.
If other household members develop symptoms during this period, you do not need to isolate for longer than 10 days.