From the start of the 12C development programme in 2007, more than 40 prototype vehicles have been built by McLaren Automotive to undertake real world testing. The latest iteration of 12C concept-phase vehicles is codenamed Validation Prototype (VP). McLaren VP and XP (Experimental Prototype -- the previous phase of 12C concept car) 12Cs are being continuously tested in the UK and across Europe. More recently, an intensive extreme weather testing programme was undertaken by the McLaren Automotive development team in Arizona, USA. With temperatures peaking at 46 degrees Celsius engineers, technicians and vehicle development partners ran two VP cars and one XP car day and night over three weeks on a mixture of driving surfaces between Lake Havasu City and Flagstaff, further west in Arizona.