World War 1 (1914-1918) proved the perfect showcase for the armored car and many different types emerged when combining existing chassis designs with new armored superstructures. The armored car continued in service throughout the interwar years where they proved highly serviceable in security roles, particularly along the frontiers of the various empirical colonies dotting the world.
Prior to World War 2 (1939-1945), the Irish Army commissioned for such a vehicle and this was delivered from Leyland beginning in 1934 who added the existing armored superstructure of a Peerless Armored Car atop their "Terrier" lorry, a 6x4 vehicle. The twin machine gun turrets of the Peerless were retained though, after evaluation of the pilot vehicle, it was decided to centralize the armament into a single turret. With three more Terriers ordered in 1935, the tank turret of the Swedish L60 Light Tank was adopted for its more potent armament. Gone were the twin 0.30 caliber machine guns which were now replaced by a combination 20mm Madsen cannon and 0.30 Madsen machine gun arrangement. Armor protection for the crew of four reached 13mm at its thickest. The vehicle weighed in at 8 tons and featured a length of 21 feet, a width of 7.2 feet and a height of 8 feet.
Externally, the Leyland car exhibited a highly faceted superstructure approach. The engine remained at its traditional place ahead of the driving compartment, aspirated by a horizontal slat grille. All wheels were covered over with arching fenders. The driving compartment remained at the middle of the design and given vision slots. The driver was seated at front-right. The turret was set over the rear of the hull and given 360-degree traversal with the primary armament.
Power to the vehicle would be served through a Leyland Terrier 6-cylinder gasoline-fueled engine which outputted at up to 80 horsepower. The engine was mated to a transmission offering four forward speeds and two reverse. The wheel arrangement remained faithful to the Leyland lorry and of a 6x4 arrangement with the twin rear axles managing a dual-tire set up to contend with the weight of the armored superstructure. Operational ranges of the Leyland car reached 150 miles with road speeds maximizing at over 40 miles per hour.
By 1939, the Irish Army had accepted all of the four Leyland cars that would eventually be completed. These then began service with the 1st Armored Squadron and managed an existence throughout World War 2. In the post-war years, the line was given a revised frontal section and the original Terrier engines were replaced with American Ford V8 models of greater (155hp) output. The American Browning .303 machine gun then replaced the original Madsen fitting and a second machine gun position was added (through a ball mounting) next to the driver's position in the hull.
Into the 1970s, the Leylands were placed in reserve to make room for incoming French Panhard AML cars. In time, all were replaced throughout the Irish Army though one example eventually fell to the Bovington Tank Museum in the southern U.K. as a preserved showpiece.