Around 13,000 British nationals visit Brunei every year (source: Brunei Immigration). Most visits are trouble free.
Although there’s no recent history of terrorism in Brunei, attacks can’t be ruled out. See Terrorism
Crime levels are low, but there are occasional incidents of petty crime against tourists. See Crime.
To contact the emergency services call + 673 242 3901 (police), 991 (fire and ambulance) or 991 (emergency – crime).
If you’re abroad and you need emergency help from the UK government, contact the nearest British embassy, consulate or high commission.
Take out comprehensive travel and medical insurance before you travel.
Source Article from https://www.gov.uk/foreign-travel-advice/brunei