As coronavirus cases in Portugal go up and down, fears are growing that Britain will reimpose a quarantine for people travelling from the country, according to Reuters.

It has been less than two weeks since Britain, Portugal's leading source of tourism, lifted a 14-day self-isolation rule for travellers arriving from Portugal.

The announcement was a relief for the tourism sector, which struggled as restrictions kept visitors away over the summer.

The number of passengers arriving from Britain has grown by a whopping 190 per cent since Portugal was removed from Britain's quarantine list.

But a steady count of several hundred new cases per day over the last week raised fears Britain would put Portugal back on the list.