Desk research against primary sources, with the issuing authority linked where a page states an official fee, rule or deadline.
The statistic worth remembering is not the crime rate but the emergency number, 999, because the situations visitors actually run into are minor — a lost passport, a medical issue in the heat — rather than anything resembling crime in a top-5-ranked city. Save 999 in your phone before you need it rather than searching for it under pressure, since tourist areas are well policed but a response still takes a few minutes to reach you.
Traffic is the risk category tourists most underestimate, because pedestrian crossings and driving norms differ from many home countries, and jaywalking carries real danger on multi-lane roads built for cars rather than for the assumption that a car will stop. Treat the heat the same way: dehydration builds quietly rather than announcing itself, so drink water on a schedule during the day rather than waiting until you feel thirsty.