Eventually, these 'AI' units would be fitted into the fighters so that, once directed onto a target by the ground controllers, they could 'lock on' to the enemy and thus maintain their strategic advantage. It was 'Taffy' Bowen who was seconded to this complex research and it was to be carried out at Bawdsey…

Whilst the RAF senior staff were skeptical of the value of ground control, one senior figure was not, Air Chief Marshal Dowding and
he suggested that a set of code words be developed to contact pilots in battle. A whole series of scenarios were worked out for both ground contact to flight leaders and vice versa…

the system became known fondly as 'Pipsqueak'

The experiments were repeated in the Autumn of 1937 using the 5 CH stations then in existence and the results were judged to be very pleasing indeed.