Reluctant to take a complete squadron out of frontline service, Air Chief Marshal Arthur 'Bomber'Harris instead decided to form a new one for the Dams raid. On March 17th 1943 he wrote to Air Vice Marshal Ralph Cochrane, Commander of No 5 Group, explaining that a weapon had been designed for use against dams, and that a new squadron was to be formed within 5 Group to train with and then deploy the weapon. Harris laid down five principles for selecting personnel and equipment. 1.The majority of aircrew were to have completed one or two operational tours and the remainder to be specially selected. 2.Special attention was to be paid to the efficiency of ground officers and in particular the Armaments Officer. 3.Groundcrews were to be provided, as far as possible, from group resources, and all were to have experience on Lancaster aircraft. 4.Aircraft were to be provided from existing squadrons, but would later be replaced by specially modified versions of the Lancaster. 5.This squadron was to be given priority over everything else, and all endeavours were to be made to form it into an efficient unit by the earliest possible date. Selected to command the new Squadron was Wing Commander Guy Gibson. A very experienced 24 yr old pre-war officer. His first operation had been with No 83 Squadron, flying Hampden I bombers, on Sept 3rd 1939, the day war was declared. There followed a spell with Fighter Command, flying Beaufighter IFs with No 29 squadron, during this time he scored two confirmed kills, from one of which he took a souvenir, a German pilots life preserver, which he wore on every subsequent flight. Gibson rejoined Bomber Command as Commander of No 106 squadron flying the Avro Manchester ( above image). He was by now a veteran of 170 sorties and held two DFCs and two DSOs. Gibson completed his third and final tour in March 1943 and was posted to a desk at No 5 Group on the pretext of writing a book about a bomber pilots war. However two days after arriving, he was called in to see AVM Cochrane, who asked him if he would consider forming a new squadron to undertake one more trip. Assured he would be allowed to lead the mission and have his choice of crews, Gibson agreed. Squadron X as it was initially known came into being on the 21st March 1943 at it's new home RAF Scampton, which it would share with No 57 Squadron. First to arrive was Flg Off ( soon to be Flight Lieutenant ) Harry Humphries, posted in from No 50 Sq as Adjutant. He set about organising the several hundred air and groundcrew that were posted in, the acquisition of equipment and facilities and a myriad other duties that needed attending to. On March 26th Squadron X gained a new identity, with 616 RAF squadrons already in existence, No 617 Squadron, and a Legend, was officially born........