4G: why 3: UK actually flew 7 wing shapes. Avro+HP as insurance (UK SOP: see Halifax+(Manchester) Lancaster; Hurricane+Spitfire). So strenuous was the Spec. (high and far) that insurance on the insurance was sought; simple Short Sperrin (2 built) and a jet variant of Lincoln (6 Ashtons built) were funded. We also flew wing-concept vehicles for 2 more: the AWA all-wing, and Short's aero-isoclinic wing. Vickers' simpleton was rejected, but in April,1948 won a design contract by committing to get (to be Valiant) in Service before (to be Vulcan/Victor Mks.1). Attlee in 1951 ordered 25, intended as pathfinders. The uplift to 104 was 50% US MDAP-funded to get rid of Lincoln NOW! When Mks.1 Victor/Vulcan were deployed, 24 Valiants were assigned from 1960 to Saceur as his Tactical Bomber Force, with US weapons.
cc: #1: why more/longer Vulcan Bs. Both were funded into design in November,1947; 25 of both Mks.1 were ordered 25 July,1952; both Mks.2 funded 31 May,1956. Production orders were placed on 5 March,1957 for 120 and on 30 May,1957 for 42 more, split equally. They were to carry, initially the UK gravity H-Bomb (to be Yellow Sun Mk.1), to be supplemented by "stand-off bomb" Blue Steel (Mk.1, longer range versions intended. HP schemed such a thing). Defence Policy was then re-jigged somewhat, military and industrial. 2 factors caused more Vulcan 2s to be deployed than Victor 2s:
- In September,1957 industry was invited to tender for (to be TSR.2). MoS required Teams. Sir Fred.HP confused "team" with "lead", so was deemed to be "difficult".
- January,1959: UK joined US to procure (to be GAM-87A Skybolt ALBM), Douglas Prime Contractor, Avro Weapons Research Division 29 March,1960 appointed Sister Firm. MoA accepted their input, that low-slung Victor could not carry Skybolt. Victor Mk.2 order was reduced to three Squadrons, Blue Steel, then changed to two, plus one as SR.2: total U/E of 24. Skybolt Vulcan 2 would equip 2 Wings each of 24, at Coningsby and Scampton.
Mks.2 had been intended to replace all 3 Mks.1. The Tanker Force was funded in 1958 to support fighter detachments in the Rapid Deployment Force. MBF Valiants would be chopped when Vulcan/Victor Mks.2 arrived, so were acquisition "free" to tank. Valiant's November,1964 wing fatigue required a quick decision on which Mk.1 would take over Valiant's NATO Tactical Bomber Force Task, and which would tank. TBF was U/E 24, the tanker Force was then 16: it was logical to plan that when the Mks.2 were displaced by Polaris, they would in turn replace the Mks.1. We had more Vulcan 2s than Victor 2s, so Vulcans to B, Victors to K.
All 3 V-Bomber bays were designed around UK's memory of Fat Man (10 tonnes, 62 inch diameter). No intention of risking these assets to haul iron. Valiant was used at Suez, Vulcan in Black Buck because they were there. Staff had no operational feedback, in Nov.1964, on comparative low-level/fatigue issues.
(Mostly, this is from Wynn's Strategic Nuclear Force Official History)