The UK government’s approved list of corridors has slowly decreased in size in recent weeks, as more countries and territories have been removed. The initial list featured more than 70 countries when it was first released in July, with those listed considered safe for UK nationals to travel to without having to self-isolate on their return. However, recent spikes in coronavirus cases has seen several countries removed, meaning travellers who visit these countries must complete a 14-day quarantine when they return home. Which countries could be removed? Three more countries are at risk of being removed from the list of approved travel corridors, forcing any travellers from these destinations to self-isolate on arrival back in the UK. The countries at risk include: ItalyMainland GreeceSweden Why are these countries at risk? Countries that have an infection rate above the threshold of 20 cases per 100,000 people risk having quarantine restrictions being reimposed. Mainland Greece had already reached this threshold last week, but it remained as one of the UK’s ‘safe’ travel corridors. The rate has since climbed to 21.4 in the last seven days, meaning it could be at risk of being removed. Currently, several Greek islands already require returning UK travellers to self-isolate, including Lesvos, Tinos, Serifos, Mykonos, Crete, Santorini and Zakynthos (Zante), due to the assessment of coronavirus risks. Similarly, Sweden has a rate of 24.7 cases per 100,000 in the last week, while Italy is also approaching the quarantine threshold, with a rate of 19.3 cases over the past seven days. While these countries are all above or on the border of the threshold of 20, the infection rates are actually well below the rates here in England, which is currently much higher at 57.3 per 100,000. While these countries are all above the threshold of 20, the infection rates are actually well below the rates here in England, which is currently much higher at 57.3 per 100,000. When will the travel corridors be reviewed? The latest UK government review of the travel corridor list took place on Thursday (1 October) evening. Announcements regarding the list are then made by Transport Secretary Grant Shapps, with any new restrictions being imposed from 4am on the following Saturday. Any countries that are removed from the list of travel corridors are then added to a quarantine list, which means travellers must self-isolate for 14 days on returning to the UK. On 1 October, Mr Shapps announced that Turkey, Poland, Bonaire, St Eustatius and Saba will be removed from the travel corridor list. This means that travellers who arrive in the UK from these destinations will need to self-isolate for 14 days as of 4am on Saturday 3 October. More than 60 countries and territories still remain on the travel corridor list, allowing people to return to the UK without having to quarantine. However, many of these countries have their own coronavirus restrictions in place for UK travellers, meaning it is still possible you will have to self-isolate on arrival at your destination. A version of this article originally appeared on our sister site, Yorkshire Evening Post.