The work of the RAFs 100 Group remains one of the least known aspects of the 1939-45 war. Even less has been written about the specifics of day-to-day electronic warfare operations and the countermeasures employed. This book, the result of many years meticulous research by Squadron Leader Richard Forder RAF (Retd) redresses the balance by focussing on one the heavy units, 223, and its sister units at RAF Oulton, Norfolk.