Negligence is established by a simple test of carelessness. If, on the "balance of probabilities" (meaning more likely than not), an accident has been the result of carelessness, a claim brought against the careless party will succeed. The standard of proof in civil law is lower than the standard of proof in criminal cases. In criminal cases the prosecution has to prove "beyond reasonable doubt" that a crime has been committed. If the Police do not prosecute the third party or the prosecution fails this does not mean that your claim for compensation will fail.
A breach of statutory duty may be committed by, for example, a highway authority that fails to maintain a road to a reasonable standard. A highway authority also has a statutory duty to inspect roads to ensure that they are safe for the use of traffic. Often cars and lorries will pass safely over hazards such as potholes; however, the same hazard will pose a great danger to cyclists.
If you do come to grief on a defect in the road, photographs will be invaluable evidence of the size and nature of the hazard. It should be noted, however, that the highway authority does have a defence to such claims. If it can be shown that proper inspections of the highway are carried out with reasonable frequency and the hole or defect has arisen since the date of the last inspection, a claim for compensation will probably fail.