This morning whilst driving to work I nearly had an incident which was only avoided as I braked and didnot go into the side of the other driver. 

Ill post the google map image of the roundabout: https://www.google.co.uk/maps/@55.0394922,-1.5923253,158m/data=!3m1!1e3?hl=en

I was travelling from right to left. As you can see there are two lanes. A clio was at the roundabout at the same and we both left the roundabout at the same time, we both go round and he decides to cut infront of me, instead of giving way and entering my lane before exiting. 

Why do people do this? The stupid thing is they then joined the a1 later on and sat doing 50mph down towards the river! Not like they were in a rush! 

It is because the lane markings are confusing. On entering the roundabout both lanes are marked for "straight ahead" but in reality, "straight ahead" is a single carriageway/merge in bend, so the right hand lane should only be marked as right only in my opinion.

Giving way while on a roundabout is a tricky subject... by their design there should be no need for cars to give way to each other when on the roundabout, but stupid road markings like this mean it happens all the time. 

its a bit stupid to have the 2 lanes going straight ahead when on the exit there is only one exit really: ) 

5 hours ago, mills705 said:

its a bit stupid to have the 2 lanes going straight ahead when on the exit there is only one exit really: ) 

Exactly, I personally don't see the point in it and although I am the last one to excuse poor driving - it is easy to get into that situation if you are driving in an unfamiliar area and come across such a roundabout/lane situation.