Firstly, take all the precautions you would do with any accident and try to remain calm.
Ensure you get yourself and others to a place of safety. If needed call the emergency services.
Then, when you are safe, please call AX as soon as you can on 01675 434667, so we can get help to you as soon as possible.
If you are able to take photos of the vehicles and circumstances, that would be very helpful, also any witness details and do exchange details with the third party involved.