AIBU to think I have no liability here? (diagram attached)

I think she was in the wrong, but I've seen a lot of these go 50/50.
If you look up the case law of Grace vs Tanner, you can't assume someone will take the exit.

So you have dashcam footage of it as you mention watching back a video?

If she really did suddenly swerve into your path I assume that could make a difference.

You'd need a video or witnesses for that though surely, as they're going to assume she was driving all the way round in the left and you didn't check you were clear of her before exiting.

The other driver's story doesn't make sense. She says she was going straight on (in which case she would be totally in the right and you're liable) but her road position suggests that she was trying to go back around the roundabout. Is she lying? Was she distracted?

I see why others are saying you have some liability but I wonder if there is a case to be made for the other driver causing the accident through careless driving?

One thing you should take away from this OP is always to assume other drivers are stupid idiots who can do anything at any time!

Couldn't see that easily on my phone and was going by the text description that suggested a dual carriageeay started somewhere after the exit. That changes things (hence my caveat), especially given dash cam availability, my suspicion is that OP will probably not be held liable, although until the insurance company has had an argument between departments, who knows for sure...

The front wheels comment was directed at the OP. If the Green car is still on her front left as she prepares to exit straight-on into lane 2, it is always good to check that the Green car has gone, or is going, where you think it is going to go.

The issue will be, I suspect, that as you entered the lane the other car was in without checking it was clear it will be 50:50. Yes, the other car was in the wrong lane, but you crossed into it when there was already a car there. Everyone makes mistakes - someone being in the wrong lane doesn't give you the right to drive into them!

It might help you in supporting 50/50 if she tries to argue it's 100% your fault for driving into her

The exit very clearly does have two lanes though...

Assuming the exit doesn't have two lanes...

The insurance situation is that you are at least partially liable. You are crossing a lane of traffic to leave the roundabout. It doesn't matter why the car is there, you cannot cross a lane of traffic that isn't clear.

No, because you still drove into the side of her. She may have been in the wrong place but that doesn’t absolve you of your responsibility to pay attention.

@HurryUpHilda Good answer . 'Always expect the unexpected ' is great advice for drivers - and remember that there are plenty of idiots and incompetents on the road as well as people who just aren't paying attention or are unsure where they're heading. The tip about looking for other clues such as alignment of wheels or direction of gaze is also good advice. There are lots of clues that help you anticipate what other road users might do and it's interesting and educational to look out for them.

No. Still a 50/50 case.

Please, please, please can we all stop saying blue was in the wrong lane.
Unless road markings explicitly direct drivers using both the first and second exit to use the left hand lane (and the outside lane is reserved for vehicles doing a U turn only?) then both lanes are permissible for vehicles going straight ahead in a two on, two off, scenario.

Except, the OP was the one who hit the other car. That car would have been to the side of the OP for some time, it didn't spawn in front of her.

A good tip on roundabouts is to watch the other cars front wheels, the car will only go where the front wheels are pointing regardless of indicators or road markings.
Everybody seems to think it is 50-50, I would be pretty miffed if it was called against me.

If she could see the other cars front wheels, then the other car was in front of her and she drove into it! That makes her even more responsible!

It will likely be be 50/50, I follow a chap called Jobber on Tiktok who was an insurance clerk and did that job for over a decade. Lots of videos on his channel from dash cams of accidents or near accidents. But yours comes under this

Precedent set in case law Grace and Tanner which is basically this

never assume someone is in the correct lane on a roundabout and if you are in the lane closest to the centre and you have to cross a lane whether cars should be continuing in that lane or not you have a duty of care to check it is safe and clear to be able to cross that lane and exit the roundabout. If you are unsure you should not exit.

This is her fault because she carried on round the roundabout incorrectly but you also exited the roundabout without making sure it was safe to do so. Sorry but you need to learn to position yourself in a staggered formation so you are never directly next to a car to avoid this happening.

https://vm.tiktok.com/ZNdf64NPb/

Look at the bigger picture, OP is going R at the next roundabout. The blue line is a totally legitimate line to take (and saves faffing about with a lane change on the short stretch of dual carriageway that she is joining). Green can only legitimately go left or exit ahead into lane 1.
Always expect the unexpected, one time in a thousand Green will continue round in front of you. A good tip on roundabouts is to watch the other cars front wheels, the car will only go where the front wheels are pointing regardless of indicators or road markings.
Everybody seems to think it is 50-50, I would be pretty miffed if it was called against me.

Chat GBT agrees with you OP

Thank God the legal system doesn't rely on Chat GPT yet!

They were both in the wrong lane.

I think she was in the wrong lane. However, did you signal left and check your mirror before exiting the roundabout? If you had, you would have seen her and maybe (if you could tell she wasn't leaving the roundabout) been able to avoid the collision. Still, I think she was at fault.

Chat GBT agrees with you OP

1. You (Blue):
2. Approached in the right-hand lane (which is acceptable for going straight on, especially at a larger roundabout with two lanes).
3. Indicated left after the first exit, as you should when exiting at the second exit.
4. Were exiting correctly and in position when the collision occurred.
5. Other Driver (Green):
6. Was in the left-hand lane, which would require her to exit at the first or second exit.
7. Instead, she cut across the roundabout from the left lane to continue around (illegally, toward an entrance-only arm), directly across your path.
8. Her claim that she was "going straight" doesn't match her actual trajectory — she was turning right from the left lane, an unsafe and incorrect maneuver.

Liability Assessment

• She was 100% in the wrong:
• She used the left-hand lane to take a right-turn maneuver, which is against the Highway Code and basic roundabout rules.
• She cut across your path while you were correctly exiting.
• There’s no valid third exit — so she was heading toward a no-entry or entrance-only road, making her movement even more unreasonable.
• Her claim of going “straight” is not just wrong, it’s demonstrably false with your diagram and the road layout.

• Misuse of lanes
• Unsafe maneuver
• Contradictory statement
• Attempted use of a non-existent or illegal exit

Both wrong

I was very much taught to use either lane. I learnt in 2004.