The new rules took hold at midnight Saturday, hours after being announced, causing uncertainty for holidaymakers and leading to criticism from travel industry leaders.

"I think it's quite poor that they did it so instantaneously," Philip Bradby, 55, told the domestic Press Association after returning early to Britain from Barcelona.

But Foreign Secretary Dominic Raab said the government was required to take "swift" action.

"The data we got was on the Friday, it showed a big jump right across mainland Spain. That was then assessed yesterday afternoon and we took the decision as swiftly as we could," Raab told Sky News' Sophy Ridge On Sunday program.

"We can't make apologies for doing so," he added.

"I understand it is disruptive for those going through this ...but we must though be able to take swift, decisive action."

Passengers arriving in Britain will have to self-isolate for two weeks following the surge in cases.

"The Joint Biosecurity Centre together with Public Health England have updated their coronavirus assessments of Spain based on the latest data," said a British government spokesman.

"As a result, Spain has been removed from the lists of countries from which passengers arriving in England, Scotland, Wales and Northern Ireland are exempted from the need to self-isolate."

Britain is advising against all but essential travel to mainland Spain, but that does not apply to the Canary Islands or the Balearic Islands. 

Barely a month after Spain ended its months-long state of emergency, new infections have been rising.

Transport minister Grant Shapps was caught in the ruling as he is currently in Spain for his summer break.

Labor called the decision "frankly shambolic", with shadow health minister Jonathan Ashworth saying holidaymakers had been left "confused and distressed".

Tui, Britain's biggest tour operator, said the government should have given them "more notice of this announcement".