However, Wellington did not use the corps as tactical entities, and continued his accustomed practice of issuing orders directly to divisional and lower commanders.

The Haldane Reforms of 1907 established a six-division British Expeditionary Force (BEF) for deployment overseas, which did not envisage any intermediate headquarters between GHQ and the infantry divisions.

It later fought a delaying action against Alexander von Kluck's German First Army in the Battle of Le Cateau which allowed most of its surviving forces to escape.

The corps crossed to France to join the British Expeditionary Force (BEF) at the end of September 1939 and at once moved up to the Belgium–France border.

[18] It took part in the advance into Belgium to resist the German invasion, and was then pushed back with the rest of the BEF to Dunkirk during the Battle of France.

On 29 May 1940, Brooke was ordered back to Britain to form a new force, and he handed over temporary command of II Corps to Maj-Gen Bernard Montgomery of 3rd Division.

Order of Battle at Dunkirk[20] GOC: Lieutenant-General Alan Brooke (until 30 May 1940)Maj-General Bernard Montgomery (acting from 30 May 1940) After commanding forces in the United Kingdom, from Lower Hare Park near Newmarket within Eastern Command,[29] II Corps was being disbanded in early 1944 when selected to be one of the two corps comprising the notional British Fourth Army, which under the deception plan Fortitude North was supposed to attack Norway.

The corps was transferred to First United States Army Group (FUSAG) in early June 1944 and moved to Lincolnshire; restored to Fourth Army when that formation joined FUSAG for Fortitude South II, headquarters now at Tunbridge Wells in Kent, with under command the British 55th and 58th divisions and the British 35th Armoured Brigade.

It was notionally part of First Canadian Army in the deception Operation Trolleycar II (threatening an attack on the Germans in the Netherlands) in November 1944.

They were installed the next day, Bank Holiday Monday, in the old underground wartime HQ under the Thames, the Montagu House Annex of the War Office.