Fighter Command was divided into fighter groups that had a specific part of Britain to guard during the Battle of Britain. However, it was perfectly feasible for sectors from one group to be sent to another sector of another group to support that group need during a heavy attack.
Fighter Command was divided into four groups for the duration of the Battle of Britain. Hugh Dowding was in overall charge of Fighter Command.
No 10 Group had two sectors in it – Middle Wallop and Filton. No 10 Group covered South-West England, the Bristol and Bath area and South Wales.
In August 1940, Middle Wallop was home base for No 238 Squadron (Hurricanes), No 604 Squadron (Blenheims), No 609 Squadron (Spitfires) and No 152 Squadron (Spitfires), which was based at RAF Warmwell.
Filton was home base for No 87 Squadron (Hurricanes), No 213 Squadron (Hurricanes, No 92 Squadron (Spitfires) and No 234 Squadron (Spitfires). 87 and 213 were based at Exeter, 92 was based at RAF Pembrey and 234 was based at RAF St. Eval.
No 11 Group was made up of seven sectors – its size was representative of the significance of where it was based. The seven sectors were North Weald, Hornchurch, Biggin Hill, Kenley, Northolt, Tangmere and Debden.
No 11 Group covered Southeast England including London.
North Weald had two bases – RAF North Weald and RAF Martlesham. No 56 Squadron was based at North Weald (Hurricanes) as was No 151 Squadron (Hurricanes). No 25 Squadron (Spitfires) and No 85 Squadron (Spitfires) were based at RAF Martlesham.
Nos 41, 65 and 74 Squadrons were all based at Hornchurch. All three squadrons flew Spitfires.
Biggin Hill had three bases – Biggin Hill (used by No 32, No 600, No 610), Gravesend (used by No 501) and Manston (used by No 600)
32 and 501 flew Hurricanes; 610 Spitfires and 600 Blenheims.
Kenley had two bases – RAF Kenley and Croydon. Nos 64 and 615 Squadrons flew out of RAF Kenley while No 111 Squadron flew out of Croydon. 615 and 111 flew Hurricanes while 64 flew Spitfires.
Nos 43 and 257 Squadrons flew out of Northolt (including Hendon) and both flew Hurricanes.
Tangmere was the host to Nos 1, 266, 601 and 145 Squadrons. 266 flew Spitfires while the others flew Hurricanes.
Debden was home to No 17 Squadron, which flew Hurricanes.
No 12 Group had five sectors in it – Kirton in Lindsey, Digby, Wittering, Duxford and Coltishall.
No 12 Group covered the Midlands and East Anglia
RAF Kirton was home to No 222 Squadron, which flew Spitfires and No 264 Squadron, which flew the Boulton Paul Defiant.
RAF Digby hosted three Squadrons – 29, 46 and 611. No 29 Squadron flew Blenheims, No 46 flew Hurricanes and No 611 flew Spitfires.
RAF Wittering was home to No 23 Squadron, which flew Blenheims and No 229 Squadron that flew Hurricaanes.
RAF Duxford hosted No 19 Squadron, which flew Spitfires.
RAF Coltishall was home to No 66 Squadron (Spitfire) and No 242 Squadron (Hurricanes)
No 13 Group was made up of six sectors – Wick, Dyce, Turnhouse, Usworth, Catterick and Church Fenton.
No 13 Group covered Scotland and Northern England.
Wick was home to Nos 3 (Hurricanes), 804 (Gladiators), 232 (Hurricanes), 504 (Hurricanes), 808 (Fulmars) and 141 (Defiant) Squadrons.
Wick itself was comprised of four different bases – Wick, Sumburgh, Castletown and Prestiwck.
Dyce, based at RAF Grangemouth, was home to 263 Squadron, which flew Hurricanes.
Turnhouse was home to Nos 253 (Hurricane), 603 (Spitfires), 602 (Spitfires) and 605 (Hurricanes) Squadrons. 253 and 603 flew out of RAF Turnhouse while 602 and 605 flew out of RAF Drem.
Usworth hosted Nos 72 (Spitfires), 79 (Hurricanes) and 607 Squadrons and had bases at Usworth and Acklington.
RAF Catterick was home to Nos 54 and 219 Squadrons. 54 flew Spitfires while 219 flew Blenheims.
Chruch Fenton, including RAF Leconfield, hosted Nos 73 (Hurricanes), 249 (Hurricanes) and 616 (Spitfire) Squadrons.