DEAR Angela Callan
Thanks for your concern,
UK passport need visa to enter the country at the moment even for 4 days.
It is informed that due to the COVID-19 outbreak recently, The Vietnam Government will deny to issue visa on arrival or evisa for ALL NATIONALITIES (even if they already had the approval letter)
This decision will be effective from 12:00 (noon), 15 March 2020 for 30 days, and not be applicable to entrants for diplomatic or official purposes,
Please cancel your trip and wait until everything is getting better.
Stepfano Tran (Mr. )