Why does the harbour of London not freeze during winter?

The harbour of London does not freeze during winter primarily due to the moderating effect of the River Thames, which flows through the city. The movement of water helps to prevent ice formation, as flowing water tends to remain warmer than still water. Additionally, the urban heat generated by buildings and infrastructure contributes to maintaining a slightly elevated temperature in the area. Lastly, the relatively mild climate of the region, influenced by the North Atlantic Ocean, also plays a role in preventing freezing.