| 21st Army Group | |
|---|---|
 Formation badge designed by General Sir Bernard Paget DSO, MC 1943 | |
| Active | 1943–45 |
| Country |  United Kingdom |
| Branch |  British Army |
| Type | Army Group |
| Size | 1,020,581 officers and men (excluding US forces) 9,248 tanks 6,584 artillery pieces 1,600 aircraft (2nd Tactical Air Force)[1] |
| Part of | Allied Expeditionary Force |
| Engagements | |
| Commanders | |
| Notable commanders | Bernard Paget Bernard Montgomery |
The21st Army Group was a British headquarters formation formed during theSecond World War. It controlled twofield armies and other supporting units, consisting primarily of theBritish Second Army and theFirst Canadian Army. Established in London during July 1943, under the command ofSupreme Headquarters Allied Expeditionary Force (SHAEF), it was assigned toOperation Overlord, theWestern Allied invasion of Europe, and was an importantAllied force in theEuropean Theatre. At various times during its existence, the 21st Army Group had additional British, Canadian,American, andPolishfield armies orcorps attached to it. The 21st Army Group operated in Northern France, Luxembourg, Belgium, the Netherlands and Germany from June 1944 until August 1945, when it was renamed theBritish Army of the Rhine (BAOR).
Commanded byGeneralSirBernard Montgomery, 21st Army Group initially controlled all ground forces inOperation Overlord (theUnited States First Army andBritish Second Army). When sufficient American forces had landed, their own12th Army Group was activated, underGeneralOmar Bradley, and the 21st Army Group was left with the British Second Army and the newly activatedFirst Canadian Army which, despite its title, also contained many British and Polish troops.[2]
Normandy was a battle of attrition for the British and Canadian troops, drawing in most of the available German reinforcements, especially armoured divisions, aroundCaen at the eastern end of thelodgement. These operations left the Germans unable to prevent theAmerican breakout at the western end of the Normandy beachhead in early August 1944. Following theGerman attack towards Mortain, the American breakout and an advance by the 21st Army Group the German armed forces in Normandy were nearly enveloped in theFalaise pocket, and subsequently routed, retreating towards the Low Countries.[3]
After the successfullandings in the south of France by theUS 6th Army Group, the 21st Army Group formed the left flank of the three Allied army groups arrayed against German forces in the West. It was therefore responsible for securing the ports upon which Allied supply depended, and also with overrunning GermanV-1 andV-2 launching sites along the coasts of westernFrance andBelgium.[4]
By 29 August, the Germans had largely withdrawn across theSeine River without their heavy equipment. The campaign through Northern France and Belgium was largely a pursuit, with the ports – formally designated "Fortress Towns" by the Germans – offering only limited opposition to the First Canadian Army. The advance was so rapid, 250 miles in four days, thatAntwerp, Belgium, was captured undefended on 4 September 1944 and the port facilities were cleared of the German defenders in the following days.[5]
On 1 September 1944, the 21st Army Group was relieved of operational control of the American armies, and those armies formed the12th Army Group.[6] At the same time, Montgomery was promoted to Field Marshal.
By mid-September, elements of 21st Army Group had reached the Dutch border, but were halted due to lack of supplies, and by flooding caused by the widespread German demolition of Dutch dikes. German control of some of the channel ports and the approaches to Antwerp, and previous Allied bombing of the French and Belgian railways, resulted in a long supply line from Normandy served mainly bytrucks.[7]
After the break-out from Normandy, there were high hopes that the war could be ended in 1944. In order to do so, the last great natural defensive barrier of Germany in the west, theRhine River had to be crossed.Operation Market Garden was orchestrated to attempt just this. It was staged in theNetherlands with theairborne troops of the American82nd and101st and one British1st airborne divisions and the1st Polish Parachute Brigade (attached to the 1st Airborne Division) being dropped to capture bridges over the lower Rhine before they could be blown by the Germans. The airborne formations were then to be relieved by armoured forces of theGuards Armoured Division advancing rapidly northwards throughEindhoven andNijmegen toArnhem, opening the north German plains, and the industrialRuhr Valley, to the Allies.[7]
However, the British armoured forces had only one main highway to operate on, and crucial information about the German forces in the operational area was either missing or ignored. The scratch forces remaining after the retreat from France were much stronger than expected, thus giving the armoured units of theXXX Corps a much tougher fight than had been anticipated, slowing the advance. The 1st British Airborne Division in Arnhemwas practically destroyed during the battle.[8]
The advance stopped south of theLower Rhine, resulting in a narrow salient that ran from the north of Belgium across the south-east of the Netherlands and was vulnerable to attack. German assaults in this salient, particularly north of Nijmegenwere repelled.[9]
The thin salient was then expanded Eastwards withOperation Aintree which saw bitter fighting around the town ofOverloon. To the WestOperation Pheasant was conducted which resulted in the liberation of the cities ofTilburg and's-Hertogenbosch broadening the front line.[10]
Since the approaches to the port ofAntwerp had not been cleared when the city was captured it had allowed the German army time to reorganise and dig in along the approaches making the port completely unusable.Thus an operation was needed to clear the approaches and thereby ease the supply problem. The island ofWalcheren was strongly held by German forces and commanded the estuary of theScheldt which flows through Antwerp. Operations byII Canadian Corps cleared the approaches to Antwerp both north and south of the water during theBattle of the Scheldt. Walcheren itself was captured in late 1944 by the last major amphibious assault in Europe in the Second World War. A combination of British and Canadian forces andRoyal Marines undertook the operation.[11]
After the capture of Walcheren came the last great German offensive of the war in the west. In a repeat of their 1940 attack, German formations smashed through weak Allied lines in theArdennes in Belgium. TheBattle of the Bulge presented a command problem to GeneralEisenhower. It had sliced through US lines, leaving some American formations north and south of the new German salient. However, the headquarters of the US 12th Army Group lay to the south, and so Eisenhower decided to place American forces north of the "Bulge" salient under 21st Army Group. They, with theUS Third Army under GeneralGeorge S. Patton, reduced the salient.[12]
After the battle, control of the First US Army which had been placed under Field Marshal Montgomery's temporary command was returned to Bradley's 12th Army Group. TheUS Ninth Army remained under Montgomery longer, before being returned to American command in Germany.[13]
Prior to the Rhineland Campaign the enemy had to be cleared from theRoer Triangle duringOperation Blackcock. This large methodical mopping up operation took place between 14 and 27 January 1945. It was not planned to make any deep thrust into the enemy defences or capture large numbers of prisoners. It proceeded from stage to stage almost entirely as planned and was completed with minimal casualties.[14]
Allied forces closed up to the Rhine by March 1945.[15] 21st Army Group at this time comprised the British Second Army under GeneralMiles Dempsey, the First Canadian Army underGeneralHarry Crerar and the US Ninth Army, under GeneralWilliam Simpson.[16]
The First Canadian Army executedOperation Veritable in difficult conditions fromNijmegen eastwards through the Reichswald Forest then southwards.[17] This was to have been the northern part of a pincer movement with the US Ninth Army moving northwards towardsDüsseldorf andKrefeld (Operation Grenade), to clear the west bank of the Rhine north ofCologne. However the Americans were delayed by two weeks when the Germans destroyed theRoer dams and flooded the American route of advance. As a result, the Canadians engaged and mauled the German reserves intended to defend the Cologne Plain.[18]
InOperation Plunder, starting on 13 March 1945, the British Second Army and the US Ninth Army crossed the Rhine at various places north of the Ruhr and German resistance in the west quickly crumbled. The First Canadian Army wheeled left and liberated the northern part of the Netherlands and captured adjoining areas of Germany, the British Second Army occupied much of north-west Germany[19] and the US Ninth Army formed the northern arm of theenvelopment of German forces in theRuhr Pocket and on 4 April reverted to Omar Bradley's 12th Army Group.[13]
On 4 May 1945, Field Marshal Montgomery accepted theunconditional surrender of the German forces in the Netherlands, in north west Germany and Denmark.[20]
After the German surrender, 21st Army Group was converted into the headquarters for theBritish occupation zone in Germany. It was renamed theBritish Army of the Rhine (BAOR) on 25 August 1945 and eventually formed the nucleus of the British forces stationed in Germany throughout theCold War.[16]
The main constituent formations of 21st Army Group were theFirst Canadian Army and theBritish Second Army. In practice, neither of the two armies were homogeneously British or Canadian. Also included was thePolish I Corps, from Normandy onwards and small Dutch, Belgian, and Czechoslovak units; units of theUS Army were attached from time to time.[16]
21st Army Group (Field MarshalBernard Montgomery)
British Second Army (Lieutenant-GeneralSir Miles Dempsey).svg)
VIII Corps (Lieutenant-GeneralSir Richard O'Connor)
Guards Armoured Division
3rd Infantry Division
5th Infantry Division (arrived from Italy in March 1945)
15th (Scottish) Infantry Division
XII Corps (Lieutenant-GeneralSir Neil Ritchie)
XXX Corps (Lieutenant-GeneralGerard Bucknall (June-August 1944); Lieutenant-GeneralBrian Horrocks (from August 1944)
First Canadian Army (Lieutenant-GeneralHarry Crerar)
II Canadian Corps (Lieutenant-GeneralGuy Simonds)
I Canadian Corps (Lieutenant-GeneralCharles Foulkes) (arrived from Italy in March 1945)
1st Canadian Division
5th Canadian (Armoured) Division
49th (West Riding) Infantry Division (assigned to I Canadian Corps in March 1945)
I Corps (Lieutenant-GeneralSir John Crocker) (Command of LOS units and formations 1945)
59th (Staffordshire) Infantry Division (disbanded in August 1944)
50th (Northumbrian) Infantry Division (returned to England in November 1944 to become a training division)21st Army Group had American units attached at various times:
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