The off the top of my head answer is none of them. The rule to give priority to traffic on your right applies to traffic on the roundabout not traffic aproachining the roundabout. Im off to mull this over a bit more..

On second thoughts you need to know the vehicle class, big giant lorry, cheeky boy racer or old granny.

If they all arrive and stop at the same time 'common sense' has priority. Unfortunately in my experience its missing with a lot of drivers, so defensive driving is key taking into account the other vehicle types and drivers.

Edited by daveyjp on 29/03/2017 at 09:26

It's not a simple one, is it. Two points come to mind.

1 - In America, where there are a lot of grid systems with square intersections, many towns have '4-way Stops' with a Stop sign on every entry. It's up to each driver to decide who got there first, as that driver has right of way. Not always simple, but it usually seems to work.

2 - there's a junction near here on the A56, a slightly offset cross-roads with pedestrian lights close by. Despite both side-roads having normal Stop signs and the usual road markings, some drivers on the main road persist in confusing everyone by making up their own rules and inviting drivers on a side road to enter the traffic. This often helps one person (assuming he interprets the flashing correctly) while hindering several others.

So, reverting to topic, maybe the driver who reached the roundabout first should have right of way?