caused toxic fumes to enter the fighting compartment, endangering the crew's health. Engine The original engine was the Jaguar J60 Mk 100b 4.2-litre petrol engine, which was replaced by a Cummins or Perkins diesel engine. The maximum speed was about and it could accelerate from standing to in 16 seconds. The maximum speed on water (with the flotation screen deployed) was . The Irish engineering company IED replaced the Jaguar engine in Irish Army Scorpions with a Steyr M16 TCA HD engine (6-cylinder, 145 kW), making the Scorpion more powerful and more reliable in critical environments. Armour The FV101 was a very light armoured vehicle, weighing in at a mere 8 tonnes. This meant some compromises had to be made on protection. The vehicle had 12.7 mm of sloped aluminium armour, giving an average effective thickness of 25 mm. The FV101 had all-around protection from shell fragments and 7.62 mm rounds, and the heavily sloped frontal arc was designed to be resistant to 14.5 mm rounds fired from . The initial manufacture of the aluminium armour resulted, after time and effects of the environment, in failure; "Stress Corrosion Cracking" (SCC) which seriously affected all early builds. Other systems The vehicle was fitted with a nuclear, biological, chemical protection system, image intensification sights for gunner and driver and a floatation screen. A commode was located under the commander's seat. An internal water tank and a boiling vessel for cooking and heating water were also provided. Service history The Scorpion was or is used by the armed forces of Belgium, Botswana, Brunei, Chile, Honduras, Iran, Indonesia, Ireland, Jordan, Malaysia, New Zealand, Nigeria, Oman, Philippines, Spain, Tanzania, Thailand, Togo, Venezuela and the United Arab Emirates. Iranian army acquired 250 Scorpions in the late 1970s and a number of them are still in use after being refurbished locally as the Tosan tank. The Scorpion was on occasion deployed to main UK airports as a measure against possible terrorist threats, e.g., Operation Marmion at Heathrow Airport in 1974. Similar operations in 2003 used the then-current Scimitar. Combat use B Squadron, Blues and Royals were airlifted and deployed into the Akrotiri and Dhekelia Sovereign Base areas, during the Turkish invasion of Cyprus 1974. Two troops from B Squadron, Blues and Royals served in the Falklands War. One troop was equipped with four Scorpions, the other with four FV107 Scimitars. These were the only armoured vehicles used