Defendant was negligent by failing to appreciate the potential danger to traffic travelling in the outside lane of a dual carriageway and seeking to use a roundabout exit, where she had missed that turning and continued around the roundabout in the nearside lane.Appeal by the claimant ('G') from the decision of HH Judge Coates dated 15 October 2002, dismissing her claim against the defendant ('T') for personal injuries sustained in a road traffic accident. The accident occurred at a roundabout on the A23 dual carriageway. Both parties were travelling in the same direction and intended to continue on the A23 heading south. T was in a car in the inside lane of the dual carriageway. G was riding a motor cycle and was travelling in the outside lane. As T manoeuvred around the roundabout she kept to the inside lane and assumed that the exit for the continuation of the A23 was straight on, or at the twelve o'clock position. However, the A23 exit was in fact between the ten and eleven o'clock positions, and it was not until T was positioned at the mouth of the exit that she realised that it was her turning. Accordingly, instead of breaking sharply or swerving into the exit, T carried on with the intention of going around the roundabout to approach the exit again. In doing so she remained in the nearside lane and was struck by G's motor cycle in the outside lane as G attempted to take the A23 turning. It was part of G's case that she assumed, by T's presence in the nearside lane, that she was going to take the A23 turning. The judge took that into account but found that T had kept to the same lane, did not make any sudden movements or swerving, and accordingly found that she simply missed her turning for which she could not be said to have been negligent. The judge concluded that the accident occurred because G had failed to keep a proper look out and made a dangerous assumption that T was intending to take the turning. The judge accordingly dismissed the claim. This was G's appeal from that decision in which she accepted that she was to some extent negligent, but argued that T was equally negligent and that the judge erred by failing to consider that both parties might have been negligent. G argued that T's negligence arose by her failure, when she realised that she had missed the exit, to look to see if anyone was coming around her in the outside lane. Had she done so, G argued, T would have seen that by continuing around the roundabout would have meant that she cut across the passage of G.HELD: (1) When a driver, in the nearside lane of a dual carriageway, approached a roundabout, and after passing the first exit approached another that was not the intended route, that driver had to be aware of another driver in the outside carriageway who wanted to take that exit. (2) In the present case, T failed to appreciate that scenario and was accordingly negligent. She failed to appreciate the potential danger to traffic seeking to use the A23 exit that were lulled into the belief that T was going to use that exit. (3) A division of 50 per cent was the appropriate disposal in the present case. The judge erred by failing to consider that possibility.Appeal allowed.