King Charles III's state visit to France has been postponed after a request by President Emmanuel Macron, Downing Street says, reports BBC News.
The French president said "we would not be serious and would lack common sense" to go ahead after unions called a day of pension protests during the visit.
The trip to Paris and Bordeaux had been due to begin on Sunday.
But both cities were caught up in violence on Thursday, some of the worst since demonstrations began in January.
Buckingham Palace said the decision to postpone the three-day visit by Charles III and Camilla, the Queen Consort, was due to the "situation in France".
"Their Majesties greatly look forward to the opportunity to visit France as soon as dates can be found," the statement added.
Speaking at the end of an EU summit in Brussels, President Macron said that from the moment on Thursday night when the unions announced another day of action for Tuesday, two days into the state visit, he felt it would be inappropriate for the King and Camilla to travel.
"As we have considerable friendship, respect and esteem for His Majesty and the Queen Consort and the British people, I took the initiative this morning to call [the King] and explain the situation... Common sense and friendship pushed us to propose a postponement."
The UK government added the decision had been "taken with the consent of all parties". Mr Macron said France had proposed moving the trip to early summer.
The decision is a significant loss of face for France and for President Macron. This was supposed to have been a showcase for France, introducing the new monarch to the best of French life and cementing a newly awakened friendship.
But the protests made the trip impossible. Several French cities saw violence on the sidelines of Thursday's largely peaceful demonstrations that attracted more than a million people.
The entrance to the town hall in Bordeaux was set alight. In the capital, tear gas was fired and Interior Minister Gérald Darmanin said 903 fires were lit, in a city where refuse has been left uncollected since 6 March.