The reason for their emergence in Britain, and their purpose, has been a subject of debate. It has been argued that they could have been military sites constructed in response to invasion from continental Europe, sites built by invaders, or a military reaction to social tensions caused by an increasing population and consequent pressure on agriculture. The dominant view since the 1960s has been that the increasing use of iron led to social changes in Britain.
The reasons for their presence in Britain and their intended purpose have been a topic of debate. Some argue they were military sites built against potential invasions from continental Europe, others suggest they were constructed by invaders or as responses to social issues like population growth and agricultural pressures. Since the 1960s, it has been widely accepted that iron use brought about societal changes.