 When Eisenhower was appointed Supreme Allied Commander in December 1943 , he naturally wished to take key members of his AFHQ staff , including Strong , with him to his new assignment . On New Year 's Eve , Smith met with Alan Brooke , now Chief of the Imperial General Staff , to discuss the transfer of key British staff from AFHQ to Supreme Headquarters Allied Expeditionary Force ( SHAEF ) . Brooke made some concessions but refused to transfer Strong , whom he believed could not be spared from the Mediterranean . A heated exchange resulted , with Smith demanding Brooke explain how Operation Overlord could be a success if the British Army withheld its best talent . Later Brooke complained to Eisenhower about Smith 's behaviour . Accordingly , another AFHQ hand , Brigadier John Whiteley , became G @-@ 2 at SHAEF . However Eisenhower and Smith eventually had their way , going over Brooke 's head to Prime Minister Winston Churchill , and Strong assumed the post on 25 May 1944 , with Brigadier General Thomas J. Betts as his deputy . 
