What are 'Junctions'?

A "Junction" is where roads meet or cross each other, and because of the potential danger in these situations, some basic priorities must be applied. In other words, who can proceed, and who has to wait or Give Way.
For full details of junction layouts, and procedures, refer to the "Highway Code" and "Know Your Traffic Signs". "Driving-The Essential Skills" is also an excellent reference source for this information.

General Guidelines

1) Traffic on a Major Road always has priority over traffic on a Minor Road. The road markings at junctions are important here....the Minor Road will usually have Give-Way or Stop lines.
Traffic following the road ahead normally has priority.

2) If turning right from a Major Road, you must give way to on-coming traffic.

3) If at Give-Way or Stop lines, you MUST give way to major road traffic. If turning left, you may emerge if it is clear to your right, and you will not affect traffic approaching from your left. If turning right, it should be clear for some distance in both directions.

4) At crossroads, there is an extra road to check (ahead of you), and if emerging from one of the minor roads, extra care will be needed. As a general rule : Right turns go last.
This is because turning right involves crossing the path of other vehicles.
There is more comprehensive advice in the Highway Code, and suggestions as to how two approaching cars both turning right should manoeuvre. Make sure your understanding of this is thorough.

5) Roundabouts are a special case. The Highway Code says that you should give way to the right, because that's where the traffic will be coming from.
It is worth noting that this also applies once you are on the roundabout...if a car to your right is signalling left, it is advisable to fall back (after a mirror check) to assist them in exiting the roundabout, allowing you to keep the situation safely under your control.
Also be aware that Emergency Service vehicles may go the "wrong way" round roundabouts if responding to an emergency.

6) Some junctions have no road markings (usually in quiet or out-of-the-way places). These junctions should always be approached with care, and be prepared to give way whichever direction you approach.

Summary

Major Road traffic has priority over Minor Road traffic

Right Turns go last (this does not apply at roundabouts).

At roundabouts traffic to your right has priority.

If in any doubt, be prepared to Give Way.