Barnett was transferred out of No. 234 Squadron on 13 August, and Hughes took temporary command until the arrival of Squadron Leader Joe "Spike" O'Brien four days later. By now the fighting was intensifying over southern England, and the squadron relocated from St Eval to RAF Middle Wallop, Hampshire, on 14 August. Almost immediately after Hughes landed the "Luftwaffe" bombed the airfield; several ground staff and civilian workers were killed, but No. 234 Squadron's Spitfires escaped damage. It was following No. 234 Squadron's move to Middle Wallop that Hughes began to score heavily against German fighters. On 15 August, in one of the costliest engagements of the Battle of Britain, known thereafter to the "Luftwaffe" as "Black Thursday", Hughes claimed victories (one of them shared) over two Messerschmitt Bf 110s. He again achieved dual success on 16, 18 and 26 August, all six victims being Messerschmitt Bf 109s brought down in the vicinity of the Isle of Wight. Whereas in July he had fired at his targets from a range of , it was now his habit to close to , approximately three Spitfire lengths, before delivering his final burst; he also made head-on attacks against enemy aircraft. He had a narrow escape on the 16th after his second victory of the day, when he chased a quartet of Junkers Ju 87s and had his tailplane shot up from behind by another Bf 109; he dived and forced the German to overshoot, then broke off having exhausted his ammunition firing at his former attacker. In the pub with Kay and his squadron mates that evening, Hughes jokingly told his wife, "In case of accidents make sure you marry again". On 3 September, Hughes' promotion to substantive flight lieutenant was promulgated in "The London Gazette". He claimed three Me 110s in the space of fifteen minutes south of Haslemere on 4 September, two Bf 109s while patrolling Kenley the following day, and a Bf 109 destroyed plus one probable near Dover on 6 September; he had to break off combat with the last-mentioned when its tanks ruptured, covering Hughes' canopy in oil. One of his victims on 5 September may have been Oberleutnant Franz von Werra, who was captured and subsequently became famous as "the one that got away". Hughes and his protégé, Bob Doe, claimed half of No. 234 Squadron's victories between mid-August and early September.