Final answer:
Early Britons primarily used bronze, an alloy of copper and tin, for crafting weapons and tools during the Bronze Age when they were mining tin.
Step-by-step explanation:
The material that early Britons primarily used for crafting weapons and tools during the period when they mined tin was bronze. This was part of the Bronze Age, a historical period characterized by the use of bronze, an alloy of copper and tin, for various implements and artworks. Bronze was the preferred material due to its durability and the relative ease of extracting and working with copper, and the availability of tin. When long-distance trade networks collapsed, it became difficult to access tin, which caused a shift to iron utilization during the Iron Age.