Quarantine restrictions for arrivals from Portugal have been imposed in Wales and Scotland due to a rise in coronavirus cases in the country - but the restrictions haven't been implemented in England.
The spokesman added: "In the case of Portugal, it was unfortunate that the United Kingdom government announced their decision [not to impose quarantine on travellers] yesterday before ministers from England, Scotland and Northern Ireland met and before considering the latest Joint Biosecurity Centre (JBC) data".
Justice Secretary Humza Yousaf said the decision to add Portugal came after coronavirus cases there rose above 20 per 100,000 of the population.
Wales did the same for six Greek islands, including Crete and Zante, but England and Northern Ireland resisted.More news: US military sticks with Microsoft for US$10 billion Jedi cloud contract
UK Transport Secretary Grant Shapps said it was a confusing position but the Scottish government insisted it was acting on scientific advice.
"Travel Corridor factors taken into account by JBC & Ministers inc: Covid-19 prevalence; level & rate of change; extent of in-country tests, regime & test positivity; extent of contained outbreak as opposed to general transmission; govt actions and other epidemiological information".
One mother who spent almost £1,000 (€1,122) changing her family's flights back from Portugal said the situation was "absolutely disgusting" after she discovered that the quarantine requirement wasn't being brought in in England.
Vaughan Gething, the Welsh government's health minister, said he had made the decision to impose restrictions after having "considered the clear advice from the Joint Biosecurity Centre report that travel from the. countries and territories constitutes a public health risk".More news: Montrezl Harrell, 6th NBA Man of the Year
He said he understands "the difficulties" the industry is going through but said testing at points of entry only identifies 7% of the cases.
"That's why the quarantine system that we have has got to be an important part of our repertoire, of our toolbox, in fighting Covid".
Scotland began requiring travellers from anywhere in Greece to enter quarantine from Thursday.
Mr Shapps concluded that travellers could continue to arrive in England from Portugal and Greece without having to quarantine.More news: Kyle Walker fears for his England career after red card against Iceland
However, they do not apply to England and Northern Ireland - leading to confusion and frustration among holidaymakers.