Video report by ITV News Political Correspondent Romilly Weeks
The Foreign Commonwealth Office (FCO) has changed its guidance to include the Canary Islands and the Balearic Islands in its advice to avoid all but essential travel to Spain.
Anyone travelling from those locations to the UK must quarantine for 14 days.
The self-isolation rule was announced on Saturday, but many had hoped Spain's islands would be exempt due to their low coronavirus rates.
Those hopes were crushed with an update from the FCO, which said people should avoid travelling to the islands, as well as the mainland, due to the "current assessment of COVID-19 risks in the country".
What prompted the FCO's turnaround on Spain?
An FCO spokesperson said: “We have considered the overall situation for British nationals travelling to and from the Balearic and Canary Islands, including the impact of the requirement to self-isolate on return to the UK, and concluded that we should advise British nationals against all non-essential travel to the whole of Spain.”
Downing Street earlier warned the public that "no travel is risk-free" during the coronavirus pandemic after huge disruption was caused by a change in quarantine rules.
Travel firm TUI UK has cancelled holidays to the Balearic Islands and Canary Islands following the FCO’s advice but said that the decision is damaging business for the travel industry.
The company has cancelled holidays to the islands from July 28 up to and including July 31. Holidays to mainland Spain were already cancelled up to and including August 9.
TUI said that customers due to travel to Spanish destinations up until August 9 will be able to cancel or amend their holiday or receive a full refund "or the option to rebook their holiday with a booking incentive".
TUI customers with island holidays booked from August 1 and mainland Spain from August 10 will be updated on Friday, July 31, the spokesperson said.
Jet2 said flights from the UK to the Balearic and Canary Islands from the UK will not be operational from Tuesday, July 28.
A spokesperson for the company said: “This advice also applies to customers travelling to any of our destinations in mainland Spain. We will be operating our scheduled programme of flights back to the UK from these destinations tomorrow.
“This is an extremely fast-moving situation, and we will provide a further update tomorrow.”
The government has been criticised for announcing mandatory quarantine rules, without warning, on Saturday evening - just hours before they were due to come into effect.
Labour criticised the "chaotic nature of the decision making" but Number 10 has defended the last-minute move, saying border measures and travel advice can be "changed rapidly" in order to protect the UK from coronavirus.
The situation elsewhere in Europe
The Prime Minister’s official spokesman said: “Unfortunately no travel is risk-free during this pandemic and disruption is possible and so anyone travelling abroad should be aware that our travel advice and exemption list is under constant review as we monitor the international situation.”
Spain had been experiencing a rise in coronavirus cases for several days, but the government said it received the most recent data on Friday and the Joint Biosecurity Centre conducted an "urgent review" before advising to mitigate travel from midnight Saturday.
Cases in Spain
Health Minister Helen Whately said Spain had seen a "very rapid increase in rates" of coronavirus and warned the list of safe countries is being kept "under review".
She said if other countries see rates "going up significantly and rapidly, we’ll need to take action".
There are now fears more European holidays could be thrown into disarray, with fears other countries could be struck off the 'air-bridges' list at potentially short notice.
It comes after the World Health Organization warned the pandemic "continues to accelerate" around the world, with nearly 16 million cases confirmed and more than 640,000 dead.
Both France and Germany are experiencing a spike in cases, prompting many to worry they could be next.
Close to 1.8 million holidays are likely to have been thrown into chaos by the move to remove Spain from the list, according to travel company The PC Agency.
The precarious situation in Europe
The government is urging employers to be “flexible” in allowing staff to work from home while self-isolating and it expects the majority of people were expected to comply with quarantine rules.
Three fines have been issued at the border since the measures were first introduced in early June.
While the government wants employers to support staff caught up in the rule change, it has not extended any new support of its own.
The Trades Union Congress had been calling for Statutory Sick Pay to be extended to anyone forced to quarantine who cannot work from home.
Downing Street said holidaymakers who miss out on work because of the quarantine period may be eligible for Universal Credit or employment support allowance but not statutory sick pay.
Pressed on whether ministers would review statutory sick pay eligibility, he said: “We always keep our response to the pandemic under review and we regularly assess the support available but there is support available for those in need.”
Under the rules employers are able to ask staff to cancel holidays if it means they will be out of work longer than planned, but the government says any worker who loses their job can appeal to the Advisory, Conciliation and Arbitration Service (Acas).
One person caught up in the rule change who will be isolating upon their return is Transport Secretary Grant Shapps, whose department announced the quarantines just hours after he jetted to Spain.
Number 10 said the rules apply to "ministers as they do anyone else".