Evidence is easier to gather in the days after an accident than it is months later, and in London some of it disappears quickly. CCTV is the clearest example. It is held by many different organisations, including Transport for London, local authorities, Network Rail, bus operators, shops and private car parks, and retention periods are often measured in weeks rather than months. It is worth asking about it early rather than assuming it will still be there.
Photographs are straightforward and valuable. Pictures of the scene, the position of vehicles, road markings, the condition of a pavement or a hazard, and any visible injuries all help explain what happened. If you have them, keep the originals along with the date they were taken.
Medical records from the days and weeks after the accident matter a great deal, because they document what was reported and treated at a time when nobody could have been building a claim. Keep letters, discharge summaries and appointment records, and note any treatment you paid for.
Finally, keep a record of the practical consequences. The days you could not work, the journeys you made to appointments, and the help you needed around the home are all part of the claim, and memory fades. A note kept as things happen is far more useful than an estimate a year later. Our page on medical and rehabilitation costs explains what to keep for treatment.