Proof:- On 18 May 2001 members of the Glasgow University Geological Association were travelling, in two minibuses, northwards on the A9 in Perthshire. The front minibus collided head-on with an ex-military Land Rover driven by the first defender. In the minibus the pursuer was seriously injured and four other occupants, including the driver, were killed. The driver of the Land Rover was also badly injured. The second defender was the driver of a Honda CRV vehicle, which had been previously travelling behind both of the minibuses, and, shortly before the accident, had overtaken the rear minibus. Here the pursuer sued both defenders for damages for the injuries caused to her, on the basis of the fault and negligence of either or both of them. The issue between the parties was whether the accident was caused by the first defender, who was travelling southwards on the A9 on the day in question, driving his vehicle onto the wrong side of the road and into the path of the minibus or whether the accident had been caused by the second defender in overtaking the front minibus at a time when it was unsafe to do so because of oncoming traffic in the shape of the first defender's vehicle and that the first defender was forced to take avoiding action to seek to prevent a collision between his vehicle and the second defender's vehicle. It was accepted by parties that the pursuer was not required to be put to the proof on the matter and the first defender had assumed the onus of showing that the accident was caused by the sole fault of the second defender.