Travellers from mainland Portugal to England will have to quarantine from 04:00 on Saturday, just weeks after the country was previously declared exempt.
Wales and Scotland had already imposed the mandatory two weeks of self-isolation from 4 and 5 September.
Quarantine-free travel is still allowed from the Portuguese islands, the Azores and Madeira.
People travelling from Hungary, French Polynesia and Reunion will also be required to self-isolate.
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