I te 10 o Paenga-whāwhā 1940, e whitu marama i muri i te pakarutanga o te Pakanga Tuarua o te Ao, i whakatairangahia a MacMillan ki te kaitohutohu o te kaitohutohu, a, i tohua hei GSO1 i roto i te HQ 55th (West Lancashire) Motor Division, he raina tuatahi o te Army Army (TA). Ko te wehenga i whakahaua e Major-General Vivian Majendie, e tekau ma tahi tau te pakeke o MacMillan, e mahi ana i te Northern Command (ka neke wawe ki te Eastern Command). Ko te wehenga he hanganga hiko motumotu e rua noa iho, kaua e toru, nga parirau, a ko ia tetahi o nga kawenga mo te paruru takutai me te whakaeke i nga taunga rererangi a te hoariri mena ka uru mai te Tiamana. I te mutunga o Hune, i muri i te wehenga o te British Expeditionary Force (BEF) mai i Dunkirk me te hinga o France
I te mutunga o te pakanga, i whakahoutia te wehenga <unk> i te timatanga o te 164th me te 165th Infantry Brigades me te tautoko i nga hoia wehenga <unk> hei wehenga hiko paerewa me te taapiri i te 199th Infantry Brigade mai i te 66th Infantry Division kua whakakorehia.