F/O Gilbert was born in Revesby, Lincolnshire, on 3rd November 1919.
He was educated at Durnford School and was at Cheltenham College from January 1934 to July 1937.

Humphrey joined the RAF on a short service commission in early December 1937. After completing his ab-initio course at 7 E&RFTS, Desford on 18th February 1938, he went to No 1 RAF Depot, Uxbridge for a short disciplinary course.
Humphrey was posted to 9 FTS, Hullavington on 5th March.

Humphrey was awarded his pilots wings on 1st June 1938, completed his training and then joined 73 Squadron at Digby on 17th September.

He was sent to CFS, Upavon on 23rd October 1938 where he qualified as an instructor on 22nd December.

In January 1939 Humphrey was posted to 504 Squadron, Auxiliary Air Force as Flying Instructor.

On 3rd August 1940 he was posted from 9 FTS to 6 OTU, Sutton Bridge.

After converting to Hurricanes, Humphrey joined 601 Squadron at Debden on 16th August. He shared in the destruction of a Ju87 on 15th August, and shared a He111 on 30th.
On 31st August, he destroyed a Me110 on 31st but was himself shot down over the Thames Estuary, in Hurricane V7260. He baled out, unhurt.
On 4th September, he destroyed a Me110. Two days later he was shot down by a Me109 over Mayfield. Again he baled out, but this time he was wounded. He landed at Pembury and his Hurricane, V6647, crashed at Kippings Cross, near Pembury.

In late April 1941, Humphrey was appointed 'B' Flight Commander. A month later he was temporarily attached to 1422 Flight at Heston. He flew night sorties in a Hurricane, accompanying a Havoc in what were early tests on Turbinlite aircraft.

Humphrey was posted to 71 (Eagle) Squadron at Martlesham Heath on 3rd September 1941 as a Flight Commander.

He was given command of 222 Squadron at North Weald on 1st November, and on 23rd December 1941, he moved to Debden to take over 65 Squadron.
When the Scharnhorst and Gneisenau made their Channel Dash on 12th February 1942, the squadron was involved in combat with the German fighter cover. Humphrey destroyed a Me109 and damaged another.

On an operation escorting Bostons to Hazebrouck on 12th April 1942, Humphrey shot down a Fw190.

Humphrey Gilbert crashed on 2nd May 1942, attempting to take off from Debden in a Spitfire, with the Controller on his lap. They were said to have been going to a party. Both men were killed.

Flying Officer Humphrey Trench Gilbert is buried in Saffron Walden Cemetery, Essex.
The award of the DFC was gazetted after his death (29th May 1942).