What is the priority relationship between traffic lights and priority signs (such as 'Priority Road' or 'Give Way') at an intersection?

1. Priority signs override traffic light signals at all times.
2. When traffic lights are operating in normal cycling mode, priority signs are disregarded and drivers must obey only the traffic lights.
3. Drivers must obey whichever rule requires them to yield.
4. Traffic lights only apply to public transport; cars follow priority signs.