General Sir John Tredinnick Crocker, GCB, KBE, DSO, MC (4 January 1896 – 9 March 1963) was a senior British Army officer who fought in both world wars.

As related in Delaney's book "Corps Commanders": John Crocker was every bit the gentleman officer of his period, even if his upbringing was anything but typical.

[1][excessive quote]Over a year after the outbreak of the First World War, which began in August 1914, Crocker enlisted into the British Army as a private soldier in the Artists Rifles, a training corps for potential officers, in November 1915.

After training at the Machine Gun School at Grantham, Lincolnshire, Crocker joined the 174th Machine Gun Company, part of the 59th (2nd North Midland) Division, a Territorial Force (TF) formation then serving in the trenches of the Western Front as part of the British Expeditionary Force (BEF).

[5]He continued to serve on the Western Front, fighting in the Hundred Days Offensive, until the war came to an end on 11 November 1918 with the signing of the Armistice with Germany.

However, he did not enjoy his new profession and returned to soldiering as an infantry officer in the Middlesex Regiment (Duke of Cambridge's Own) in the Regular Army.

[10] After graduating from Quetta, he then held a number of both field and staff posts including brigade major[11][12] to Brigadier Percy Hobart's 1st Tank Brigade and General Staff Officer Grade 1 (GSO1) to Major-General Alan Brooke when the latter was commanding the Mobile Division (later the 1st Armoured Division).

Crocker was not to remain there long, however, as on 21 April 1940 he was promoted to the acting rank of brigadier and was appointed to command of the 3rd Armoured Brigade in place of Vyvyan Pope.

However, on 18 September 1940, he was promoted to the acting rank of Major-General[22] at the relatively young age of just forty-four, and became General Officer Commanding (GOC) of the newly created 6th Armoured Division.

It is quite probable that Alan Brooke, who still thought highly of Crocker and was now Chief of the Imperial General Staff (CIGS), secured for him his new appointment.

[26] Commanded throughout its existence by Lieutenant-General Kenneth Anderson, the First Army was formed to be the parent formation for the Allied forces preparing to invade French North Africa as part of Operation Torch.

Also under command for the operation was the U.S. 34th Infantry Division, under Major General Charles W. Ryder, which Crocker ordered to seize a key position to the right of the pass.

On 27 April, Crocker was wounded in a training accident, during a demonstration of a PIAT (Projector, Infantry, Anti Tank) anti-tank weapon, shortly before the final battle for Tunis and saw no further action in North Africa.

Crocker was, nonetheless, appointed a Companion of the Order of the Bath on 5 August 1943 for his command in Tunisia,[29] and General Sir Harold Alexander, commander of the Allied 18th Army Group (which controlled both the British First and Eighth Armies), believed Crocker to have performed well throughout his relatively brief time in action.

[26] Crocker's I Corps was to form part of the British Second Army, then under his former army commander in North Africa, Lieutenant-General Sir Kenneth Anderson (but replaced in January 1944 by Lieutenant-General Miles Dempsey), training for Operation Overlord, the Allied invasion of Northern France.

Despite Crocker's background in armoured warfare, I Corps was predominantly an infantry formation, but General Sir Bernard Montgomery, the Allied Land Forces Commander for D Day and the battle of Normandy 21st Army Group, had confidence in Crocker's organisational skills and assigned I Corps the difficult task of capturing the city of Caen.

[26] On D-Day, 6 June 1944, Crocker had a larger task than any other Allied corps commander: he had to control two landing beaches (Juno and Sword) and an airborne assault.

[31] The operation began on 7 July and, after heavy fighting, had captured most of the Caen city centre, although the Germans still held the southern half.

[31] Colonel Hermann-Eberhard Wildermuth in charge of German operations urged a civilian evacuation, yet only 10,000 left, as Crocker refused the proposal.

[32] The corps, losing the 3rd Division soon after and gaining Major-General Evelyn Barker's 49th Division in exchange, came under command of Lieutenant-General Harry Crerar's First Canadian Army in August 1944, I Corps drove forward to the River Seine and then took part in the unglamorous mopping up operations along the French and Belgian coastline.

[31][33] When severe British manpower shortages prompted the disbandment of two infantry divisions (the 59th (Staffordshire) and 50th (Northumbrian)) in late 1944, I Corps HQ was withdrawn from the front line to take over the administration of the 21st Army Group's rear areas in Germany as it advanced across the river Rhine in March 1945.

[37] Crocker's son, Wilfrid, a cavalry officer serving with the 5th Royal Inniskilling Dragoon Guards, then equipped with Cromwell tanks[38] and part of the 7th Armoured Division, was killed in action on 20 October 1944 fighting in the battle for 's-Hertogenbosch in the Netherlands.

[39] He remained for two years as GOC-in-C of Southern Command,[40] until in 1947 he moved on to be Commander-in-Chief (C-in-C) Middle East Land Forces in succession to Lieutenant-General Sir Miles Dempsey during the final stages of the Palestine Emergency.

[42] Created a Knight Grand Cross of the Order of the Bath (GCB) on 10 June 1948,[43] Crocker retired from the army on 29 September 1953.

[47] Crocker's most important postwar contribution was to write the training manuals that laid down the British Army's doctrine of armoured warfare through the years of the Cold War.

[50] After retiring he became vice-chairman of the Imperial War Graves Commission and Lord Lieutenant of Middlesex,[51] a position he held from 1961 until his death on 9 March 1963 at the relatively young age of sixty-seven.

Field Marshal Montgomery would have preferred it if Crocker had retired as Chief of the Imperial General Staff (CIGS), but in 1949 Prime Minister Clement Attlee chose Sir William Slim instead.