I presume that you have evidence - not just opinion - that the damage was caused by the verge cutting operation?

It happened as I was passing the grass cutter. Nothing else on the road. No trees overhead. Impact sight about 60 x 30 mm over which the top layer of glass was remover, severe cracking extending from this and glass inside the car.

It would be on the "Balance of Probabilities" - a much lower burden of proof than BRD which is reserved for criminal matters.

Have to agree :( I lost a windscreen on a random road via a random stone - it happens - country roads are good fun aren't they. However my friends windscreen had an actual golf ball stuck init and so :) I assume police were notified - what did they say / do? Was it direct impact from a cutter and could they have guarded this? or was it debris on the road kicked up by car in front? It's so difficult to comment without lots more info if you feel there is a claim then put one in.

No, I don’t think that their defence is flawed! The defence if having done all that is reasonable, is a common and often accepted defence. That AIS 25 recognises the danger from debris etc doesn’t provide you with a claim for automatic liability! I think it is reasonably likely that this was related to the use of the ‘flail’ rather than some other ‘random’ event. You have not indicated that the accident was due to a damaged machine part flying off from the ‘flail’ or whatever, and I, like most have probably assumed that this is more likely to have been from a stone or other piece of debris ‘hidden’ in the verge. Surely you recognise that the operator can’t realistically ensure absolute safety when carrying out such an operation but that rather they have to try and ensure that they have taken all REASONABLE measures? In practical terms this couldn’t possibly extend to and inch by inch examination of the verge prior to verge cutting; the ‘cost’ would be prohibitive. Similarly, I would also hope that you recognise (although this is not apparent) that although they MAY have caused the damage, that they aren’t necessarily liable for the damage? I am not quite sure if your example is necessarily pertinent or relevant. Again, you now seem to be saying that the, whatever it was that damaged your screen, was as the result of some kind of mechanical failure. Unless you can prove that it was, I would think that it is much more likely to be a stone or other piece of debris. Again, it is difficult to know whether an investigation would reveal anything to your ‘benefit’. If there is a piece of the equipment ‘missing’ how could they determine whether it did come off and hit your screen (unless you have it cunningly stashed away somewhere) or whether it came off 3 miles down the road and be lying somewhere ‘harmlessly’ in the verge. Every time I pass a verge or hedge cutter I think “oh oh”; so far I have escaped any significant damage to my car, but I also recognise that there is a chance that one day I could get ‘dinked’ by something. I am not sure if your expectation is entirely realistic. Where there’s blame there’s a claim, especially if it’s a Council!