Mills was born on 20 October 1909.

He went to Imperial Service College and joined the RAF in January 1927 as an Aircraft Apprentice (561203). He passed out in December 1929 as a Fitter, Aero Engines.

He later applied for pilot training and was selected.

Mills was a Sergeant-pilot when he was granted a Permanent Commission on 21 May 1936 and promoted to Pilot Officer.

He joined 17 Squadron at Kenley on 3 June 1936 and moved to the Station Flight at Northolt on 1 February 1937.

He was promoted to Flying Officer on 21 November 1937

He joined 263 Squadron at its formation at Filton on 20 October 1939 as a Flight Commander.

On 21 November 1939 he was promoted to Flight Lieutenant.

He served with 263 Squadron during both Norwegian expeditions.

At 09:00 on 25 April Mills took off and patrolled over Lake Lesjaskog for 30 minutes, allowing six more Gladiators to get off undisturbed. These then provided cover for the army at the front while their fuel lasted, and also spotted for the artillery.
During this patrol Mills engaged six II/LG1 He111s near a lake and was credited with shooting one down. This aircraft, a He111H of 4 Staffel, actually limped back to Stavanger/Sola, but as it approach to land, both engines failed and it crashed into the sea. The crew was however rescued.
At Lesjaskog four more frozen-up Gladiators were destroyed by air attack at 13:05, but two others then got off, flown by Squadron Leader Donaldson (in N5633) and Flight Lieutenant Mills. Over the next two and a half hours these two would engage in six major combats over the lake.
Firstly at 14:00 both pilots attacked a Heinkel of Stab/LG1 and brought it down to crash-land south of Vinstra, near Dombås.
Feldwebel Hans Gutt’s crew set fire to the aircraft, in which the badly injured wireless operator had shot himself. The survivors were subsequently captured, and the wreckage of this bomber was later inspected by British troops.
Both pilots then attacked another Heinkel from 6/LG1, which was damaged, but made it back to Fornebu with two wounded aboard.
Donaldson and Mills were both airborne again during the evening, as the last five serviceable Gladiators were withdrawn from Lesjaskog north to a temporary landing ground, which had been prepared at Setnesmoen, just outside Aandalsnes. Donaldson was scrambled, and near the new base found a He111 of II/LG1, which had been attacking a steamer near Aandalsnes. This was believed to have been shot down into a ravine, but actually the very badly damaged bomber was almost able to reach Oslo/Fornebu before the engines failed and the crew baled out.
Mills was up for a third time before twilight, having a running fight with a Ju88, but he had to make a force-landing having used up all his fuel and ammunition. As he was examining the fighter for damage, bombers appeared and destroyed it.

263 Squadron suffered heavily losses and was soon withdrawn back to Great Britain to be re-equipped.

On 10 May Mills was decorated with the DFC.

On 14 May the Squadron again sailed for Norway aboard the carrier HMS Furious.

On 21 May two sections of the squadron managed to take off from the carrier, each led by a Swordfish, to fly to their new base at Bardufoss in northern Norway. At this stage driving sleet prevented the take off of any further aircraft, and indeed one section successfully landed back on board again. The other pair set off behind their guiding Swordfish, but overcast and mist now extended down to the water in Torskenfjord, and all three aircraft flew into the mountain at Torsken. Mills was injured, but 24-year-old Pilot Officer Walter Philip Richards (RAF no. 77340) in N5693 was killed when he crashed into a mountainside at Osterfjord, Senja Island. The wreckage of N5693 has been recovered and identified.
It is possible that Mills flew N5907 since according to unconfirmed sources a serial plate with N5907 has been found on the wreckage. However according to other sources N5907 was lost with HMS Glorious on 8 June 1940.

Mills was one of the pilots who traveled back to England with the MV Arandora Star, thus avoiding the loss of HMS Glorious.

The squadron reformed at Drem but Mills was promoted on 24 August and took command of 87 Squadron at Church Fenton.

On 1 December he was promoted to Squadron Leader.

He was posted away in December to the USA, as Assistant Air Attaché, to develop British training facilities. The RAF eventually had six schools there. Mills also personally briefed MR. Roosevelt at the White House on European operations.

On 1 June 1942 he was promoted to Wing Commander.

He did not return to the UK until 1945.

Mills ended the war with 1 biplane victory.

On 1 October 1946 he was promoted to Wing Commander.

He retired from the RAF on 20 October 1956 as a Wing Commander, retaining the rank of Group Captain.

Mills died in 1996.

Claims:

Kill no.	Date	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1940
1	25/04/40	1	He111 (a)	Destroyed	Gladiator II		Lake Lesjaskog	263 Squadron
	25/04/40	1	He111 (b)	Shared destroyed	Gladiator II		S Vinstra	263 Squadron
	25/04/40	1	He111 (c)	Shared damaged	Gladiator II		Lake Lesjaskog	263 Squadron

Biplane victories: 1 and 1 shared destroyed, 1 damaged.
TOTAL: 1 and 1 shared destroyed, 1 damaged.
(a) He111H of 4/LG1 shot down. The crew was rescued.
(b) He111 of Stab/LG1 shot down to crash-land south of Vinstra, near Dombås at 14:00. The badly injured wireless operator shot himself. Feldwebel Hans Gutt and the rest of his crew were taken prisoners after setting the aircraft on fire.
(c) He111 of 6/LG1 damaged shortly after 14:00 with two of the crew wounded.

Sources:
Fledgling Eagles - Christopher Shores with John Foreman, Christian-Jaques Ehrengardt, Heinrich Weiss and Bjørn Olsen, 1991 Grub Street, London, ISBN 0-948817-42-9
Gloster Gladiator Home Page - Alexander Crawford
Men of the Battle of Britain - Kenneth G. Wynn, 1999 CCB Associates, ISBN 1-902074-10-6
The Commonwealth War Graves Commission
Additional information kindly provided by Birger Larsen.