elf-isolation for contacts of people with confirmed coronavirus will be shortened from 14 to 10 days across the UK from Monday.
The change will also apply to people instructed to quarantine after returning from high-risk countries.
And it means anyone who has been self-isolating for 10 days or more will be able to end their quarantine on Monday.
The announcement comes as data shows Covid cases falling in most of England and Northern Ireland.
But the Office for National Statistics (ONS) figures show that in the week to 5 December, there were increases in coronavirus case numbers in London and the east of England.
On Thursday, Health Secretary Matt Hancock announced mass testing would be rolled out for secondary school children, their families and teachers in the worst-affected areas of London, Kent and Essex.
The change in self-isolation rules was announced in a statement from the four UK chief medical officers (CMOs) said: "After reviewing the evidence, we are now confident that we can reduce the number of days that contacts self-isolate from 14 days to 10.