The Highway Code states that when entering a roundabout you must give priority to traffic approaching from your right, unless directed otherwise by signs, road markings or traffic lights.
This sign means:
Mini roundabout
Motorway roundabout
One-way system
Turn around
Where would you see this sign?
In advance of a mini roundabout only
In advance of a roundabout
At the location of a mini roundabout
At the location of a spiral roundabout
When waiting to enter a roundabout, you should look for a gap to drive into. The gap you intend to take should be:
Behind a vehicle approaching from the right
In front of a vehicle approaching from the right
When going ahead or turning right the DVSA state that you should signal to leave a roundabout:
Immediately after you enter
50 metres before you reach the exit
As soon as you have passed the exit before the one you want
Just before the exit before the one you want