The British 1st Armoured Division was responsible for protecting the right flank of VII Corps. It was assumed by the Corps' planners the Iraqi 52nd Armored Division would counterattack VII Corps once their penetration into Iraqi defenses was discovered. The British 1st Armoured Division had two brigades (the 4th and 7th) which participated in Operation Granby, the name given to the British military operations during the 1991 Gulf War. The 1st Armoured was equipped with the Challenger 1 main battle tank. The British 1st Armoured Division fielded approximately 176 Challenger 1 tanks. With a 120mm rifled main gun, thermal optics, and state of the art Chobham armor, its only rival in-theatre was the American M1A1 Abrams tank. British infantry rode into battle on the Warrior tracked armoured vehicle. It had reasonable armour protection and a 30-mm gun. Modified versions of the vehicle included mortar carriers, MILAN antitank systems, and command and control vehicles; and the British possessed a variety of excellent light armoured vehicles built on their FV101 Scorpion chassis. British artillery was primarily American made M109 howitzers (155mm), M110 howitzers (203mm), and M270 MLRS which were compatible with American systems. Their air support consisted of Gazelle helicopters, used for reconnaissance, and the Lynx helicopter which was comparable to the American AH-1 Cobra. The British had their full contingent of engineer, logistics, and medical units.