Fact File : Battle of Arras
21 May 1940
Area: The town of Arras in Northern France, on the River Scarpe south west of Lille.
Players: Britain: 6th and 8th Battalions, Durham Light Infantry; 4th and 7th Battalions, Royal Tank Regiment.
Germany: 7th Panzer Division; German 7th Infantry Regiment and SS Totenkopf Division.
Outcome: This British counter-attack failed, but nonetheless worried the advancing Germans and possibly contributed to the success of the Dunkirk evacuation.
As the Germans advanced rapidly towards the French coast in May 1940, the area around the town of Arras was reinforced with British Expeditionary Force (BEF) troops.
By 20 May 1940, Arras itself was surrounded but still holding out. Viscount Gort, commander-in-chief of the BEF, decided on a counter-attack codenamed Frankforce.
The attack was supposed to be manned by two infantry divisions, comprising about 15,000 men. It was ultimately executed by just two infantry battalions totalling around 2,000 men, and reinforced by 74 tanks.
The infantry battalions were split into two columns for the attack, which took place on 21 May. The right column initially made rapid progress, taking a number of German prisoners, but they soon ran into German infantry and SS, backed by air support, and took heavy losses.
The left column also enjoyed early success before running into opposition from the infantry units of Brigadier Erwin Rommel's 7th Panzer Division.
French cover enabled British troops to withdraw to their former positions that night. Frankforce was over, and the next day the Germans regrouped and continued their advance.
Frankforce took around 400 German prisoners and inflicted a similar number of casualties, as well as destroying a number of tanks. The operation had punched far beyond its weight - the attack was so fierce that 7th Panzer Division believed it had been attacked by five infantry divisions.
The attack also made the German commanders nervous, and it may have been one of the factors for the surprise German halt on 24 May that gave the BEF the slimmest of opportunities to begin evacuation from Dunkirk.
The fact files in this timeline were commissioned by the BBC in June 2003 and September 2005. Find out more about the authors who wrote them.