Do I need a visa with UK passports
Dear Mr Ranjit Singh Sidhu,
Thank you for your question.
We would like to confirm you that according to the Vietnam Immigration's new policy, from July 1, 2015 to 31 Feb 2019, 12 countries (including France, Germany, Italy, Spain, UK and Belarus, Norway, Finland and Sweden, South korea, Japan, Denmark) no need Visa if they stay in Vietnam less than 15 days. However, the previous visit must be far at least 30 days the next visit and your passport's validity must be more than 6 months.
In case you meet all above conditions, you will not need Vietnam Visa.