The countries that used the Blenheim was Britain, Canada, Finland, Greece (10), Hungary, Portugal, Romania, Turkey (17), and Yugoslavia.
The Blenheim crews suffered the most casualties than any other RAF aircraft.
RAF squadrons started receiving the Blenheims in March 1939.
The Blenheim was the RAF's principal light bomber at the beginning of World War II.
On September 3, 1939, a reconnaissance flight over flew the German border. The first RAF bombing raid was conducted by Blenheim Mk IVs. The Blenheim Mk IVs outfitted seven RAF squadrons.
- Mk IF Night Fighter: No 23, No 25, No 29, No 64, No 600, No 601, No 604
In March 1936/March 1937 the No. 114 Squadron, at Wyton, was the first unit to receive the Bristol Blenheim Mk I.
In January 1937 the first unit equipped with Blenheim Mk Is became operational. By the end of 1937 15 more units received the Blenheim Mk Is.
By the time of the Munich Crisis of September 1938 there were 16 / 17 squadrons equipped with Blenheims. Seven squadrons in No 1 Group, six in No 2 Group, and four in No 5 Group.
First Mission on September 3, 1939
The No 139 Squadron sent a Blenheim IV (N6215), flown by Flag Officer McPherson, to photograph German naval units at Wilhelmshaven. No flak or Luftwaffe units were encountered. The next day McPherson was sent out again. The 107th and 110th Squadrons attacked the German fleet. McPherson eventually received the Distinguished Flying Cross.
First U-Boat Kill for RAF
On March 11, 1940 a Blenheim Mk IV flown by Squadron Leader M. V. Delap of No 82 Squadron sank a U-Boat.
Battle of France
The Blenheims suffered heavy losses during the Battle of France.
First Night Victory
The first night AI victory was scored by a Mk IF on July 22, 1940 against a Dornier Do 17Z.
From 1939 there were 24 RAF squadrons that were equipped with the Blenheim Mk IF night fighter.
The Blenheim Mk IVs started being delivered to the Middle East in early 1940, replacing Mk Is.
The Blenheim Mk IVs last operation was on August 18, 1942.
As an anti shipping bomber the Blenheims sank 70 enemy ships from January to June 1941.
There were four squadrons of Blenheims stationed in the Far East and suffered heavily when Japan invaded Malaya.
Squadron Leader A Scarf of the 62 Squadron was awarded a posthumous Victoria Cross during these battles.
Ten Blenheim Mk IVs were built under license. The were used until 1956 in forestry and survey work.
Produced more than 600, known as the Bolingbroke. Most were used as trainers for navigation and gunnery. Some were fitted with ski gear for landing. A few were used in reconnaissance over the Atlantic.