The Foreign & Commonwealth Office has advised British citizens against all non-essential international travel, initially for a period of 30 days.
The advice takes effect immediately.
The change in advice reflects the pace at which other countries are either closing their borders or implementing restrictive measures in response to the global coronavirus pandemic.
Often there is little or no notice when countries take these steps and restrictions are also being imposed in areas where no cases of coronavirus have yet been reported, the FCO said.
They are therefore very difficult to predict.
British people who decide that they still need to travel abroad should be fully aware of the increased risks of doing so.
That includes the risk that they may not be able to get home, if travel restrictions are put in place.
Anyone still considering travel to be realistic about the level of disruption they are willing and able to endure, and to make decisions in light of the unprecedented conditions.
Foreign secretary, Dominic Raab, said: “UK travellers abroad now face widespread international border restrictions and lock downs in various countries.
“The speed and range of those measures across other countries is unprecedented.
“So, I have taken the decision to advise British nationals against all non-essential international travel.”
The FCO, however, said it was not currently advising Brits to immediately return to the UK if they are overseas.
However, they should keep in mind that flights may be cancelled at short notice or other travel restrictions may be put in place by foreign governments.
“Whether travel is essential or not is a personal decision and circumstances differ from person to person.
“It is for individuals themselves to make an informed decision based on the risks and FCO advice,” the FCO said in a statement.
UK inward and outward travel has already fallen by a significant amount since the outbreak of coronavirus.
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