General rules, techniques and advice for all drivers and riders · Lighting requirements
Rule 115: You should also use dipped headlights
You should also
use dipped headlights, or dim-dip if fitted, at night in built-up areas and in dull daytime weather, to ensure that you can be seen
keep your headlights dipped when overtaking until you are level with the other vehicle and then change to main beam if necessary, unless this would dazzle oncoming road users
slow down, and if necessary stop, if you are dazzled by oncoming headlights.
In the Highway Code, MUST and MUST NOT identify legal requirements. Advice using should, should not, do or do not can still be used as evidence in court proceedings under the Traffic Acts to establish liability. The introduction explains this distinction.
The rules either side
The Code reads in order, and each of these names the rule it goes to rather than saying only ‘next’.