Fighter Command was tasked with defending Britain against German bomber attacks, with four different groups, numbered 10–13, each responsible for a different region of the country. A hierarchical detection and command network received and relayed information about the location of incoming German bomber formations, greatly increasing the speed and accuracy of British fighter interceptions. Detection reports from coastal radar stations and the Royal Observer Corps lookout posts were relayed to a central ‘filter room’ at Bentley Priory. Under the Dowding system, Fighter Command used a central control room to maintain an accurate image of enemy formations and available RAF units across the country. Relevant information for each region was then sent to the group command rooms which in turn sent out orders to sector command airfields. In this way the often contradictory enemy tracking reports generated by using the basic detection methods available at the time could be filtered out.
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