The British government has added Sri Lanka to its “no-go” list, alongside countries such as North Korea, Iraq and Venezuela.
These are the key questions and answers.
What is the Foreign Office saying, and how has that changed?
The FCO has warned since the horrific attacks on Easter Sunday: “Terrorists are very likely to try to carry out attacks in Sri Lanka. Attacks could be indiscriminate, including in places visited by foreigners.
“The Sri Lankan authorities have made a number of arrests in relation to the attacks, and security operations are ongoing, including controlled explosions of suspicious packages and vehicles, and temporary evacuations of buildings.”
On Thursday 25 April, the Foreign Office changed the official travel advice to warn “against all but essential travel to Sri Lanka, due to the current evolving security situation”.
The FCO says: “The extent of any continued threat following the 21 April attacks remains unclear.”
What are the implications for British holidaymakers in Sri Lanka?
An estimated 8,000 UK citizens are on holiday on the island, and the advice indicates that they should leave in a timely fashion by commercial means – in other words, flying from Colombo on a scheduled flight.
Unlike the last two events in which British tourists were told to leave – both in 2015, in Tunisia and the Egyptian resort of Sharm el Sheikh – no airlift is to be established.
Tui flew an empty aircraft to Sri Lanka‘s international airport outside Colombo to bring back up to 200 holidaymakers.
Travellers who are still on the island and who are not booked on imminent departures are being advised: “Keep a low profile, avoid crowded public places, large gatherings (including religious gatherings and places of worship) and any demonstrations.
“All of the attacks on 21 April were carried out either in places of worship or in places where foreign visitors were affected. Any further attacks may be targeted against similar locations.”
So how are they expected to get home?
Those who are booked to return at the weekend will be expected to travel back as planned. Newly arrived travellers are asked to make arrangements to leave in conjunction with their travel company.
There is only one direct flight a day from Colombo to the UK – the SriLankan Airlines departure to Heathrow, which is usually heavily booked.
The situation is made more complicated by the collapse earlier this month of Jet Airways, which previously carried a significant number of British travellers between the UK and Sri Lanka via Mumbai.
Emirates and Qatar Airways have seats available from Colombo over the next few days for travel via their respective hubs in Dubai and Doha to various UK airports. But fares are extremely high – typically £800-plus for a one-way flight.
Airlines are advising arriving at Colombo airport four hours before departure, because of increased security checks.
Will travel insurance pay for an emergency flight?
A spokesperson for the Association of British Insurers said: “Travel insurance is designed to cover unforeseen events like this.
“Cancellation cover under your travel insurance should cover additional costs that cannot be refunded by your travel provider.
“If you are currently in Sri Lanka and want to curtail your visit and return early, your travel insurance should cover any extra costs associated with rearranging return flights.
“Check if you have the necessary cover in place or speak to your travel insurer.”
What if I decide to remain in, or travel to, Sri Lanka?
If you are likely to depart from the island in a timely fashion then your cover should remain in place. But for new arrivals, travelling to a country that is on the no-ho list is likely to invalidate your travel insurance.
What are the options for travellers with advance bookings for Sri Lanka?
It all depends when you are booked to travel. A spokesperson for Abta, the travel association, said: “Customers who are due to travel imminently to the island on package holidays will be offered options of deferring their date of travel, transferring to another destination or a full refund.”
The customer, not the travel company, has the choice of accepting a different holiday or claiming a full refund.
Abta also points out: “Customers who have booked independently will need to discuss their options with their airline and accommodation provider.”
But if you are due to travel in months to come, the tour operator will not necessarily offer you any options at this stage.
I have a connecting flight via Colombo. Can or should I cancel?
No. After The Independent contacted the Foreign Office to ask about the status of connections on SriLankan Airlines to the Maldives, southeast Asia and Australia, the FCO said: “The guidance advising against all but essential travel to Sri Lanka does not apply to flights transiting Colombo airport, providing that passengers remain airside in the airport.”
How long is the ban likely to last?
When he announced the ban, the Foreign Secretary, Jeremy Hunt, said: “Our hope is that it will be possible to change this when the current security operation has concluded.”
But the evidence from history suggests that the ban could last for months or years.
The Tunisia “no-go” advice was lifted after two years, while the ban on UK airlines flying to Sharm el Sheikh has now been in force for three-and-a-half years.
For every day that it continues, the damage caused to the Sri Lankan economy and the hundreds of thousands of people involved in tourism will intensify.