If you’ve been abroad you’ll need to quarantine for 10 days post arrival to the UK. You’ll also need to take a Covid-19 PCR test on or before Day 2 and on or after Day 8 of your self-isolation, in accordance to the government regulations on international arrivals outside of the UK.
Please note that the COVID-19 test for the test to release scheme is in addition to the mandatory Day 2 and Day 8 tests, therefore you must still carry out your Day 8 test in line with the government regulations even if your Test to Release result is negative.