 Henry Tizard , whose committee spearheaded development of the CH system , grew concerned that CH would be too effective . He expected that the Luftwaffe would suffer so many losses that they would be forced to call off daylight attacks , and would turn to a night bombing effort . Their predecessors in World War I did the same when the London Air Defence Area successfully blocked daytime raids , and attempts to intercept German bombers at night proved comically ineffective . Tizard 's concerns would prove prophetic ; Bowen called it " one of the best examples of technological forecasting made in the twentieth century " . 
