Planning began in 1956 when Campbell set his sights on the land speed record, which then stood at 394 mph (634 km/h), set by John Cobb in the Railton Mobil Special. The Norris brothers — Ken and Lew Norris, who had designed Campbell's highly successful Bluebird K7 hydroplane — drew up the CN7 with an ultimate target of 500 mph (800 km/h) in mind. The designation CN7 stood for Campbell-Norris 7.
Construction was carried out by Motor Panels in Coventry under the supervision of Donald Stevens of Norris Bros and Maurice Britton of Motor Panels. The car was completed by spring 1960. It weighs four tons and was built with advanced aluminium honeycomb sandwich construction of high strength, with a fully independent double wishbone suspension on all four corners. The split-rim wheels carried 52-inch (130 cm) diameter Dunlop tyres inflated to 160 psi (1,100 kPa) for record attempts.
The powerplant was a Bristol-Siddeley Proteus 705 gas turbine — the Bristol Aeroplane Company's first successful gas turbine engine design — specially modified by Norris Bros to have a power shaft at each end. The Proteus delivered 4,450 shp (3,300 kW). FIA regulations prohibited the use of jet thrust, so exhaust was directed rearward only to fill the aerodynamic wake. The power shafts connected through final drive assemblies with differentials at a fixed ratio of 3.6:1 to all four driven wheels. Braking was achieved via inboard-mounted Girling disc brakes with hydraulic and pneumatic backup systems, supplemented by hydraulically powered air brakes extending from the rear of the car; the turbine itself provided approximately 500 hp of engine braking at 400 mph. Adrian Newey, Formula One car designer, has noted that the CN7 was the first car to properly recognise and make use of ground effect.
Campbell demonstrated the CN7 at Goodwood Circuit in July 1960 for its public debut. Because the car had only four degrees of steering lock, speed on the track was limited to approximately 100 mph on the straight. The actual shakedown runs took place at RAF Tangmere. The car was then shipped to Bonneville Salt Flats in Utah, where Campbell's father Malcolm had set his final land speed record in 1935. In early September, CN7 accelerated to just under 400 mph in 24 seconds over 1.5 miles at roughly 80 percent of full power. The record attempt itself, heavily sponsored by BP, Dunlop, and other British companies, ended in disaster on 16 September when the car crashed at high speed. Campbell suffered a fractured skull base, a broken eardrum, and cuts and bruises. He convalesced in California and for a time doubted whether he would return to record breaking.
After CN7 was rebuilt — modifications included differential locks and a large vertical stabilising fin — it was shipped to Lake Eyre in South Australia for a 1963 attempt. The dried salt lake offered 450 square miles of flat surface with a 20-mile run available. Unusual rainfall flooded the lake and the 1963 attempt was abandoned, generating damaging press coverage despite circumstances being entirely beyond Campbell's control. BP withdrew its sponsorship.
Campbell returned in 1964 with funding from Australian oil company Ampol. The surface was never as smooth or as dry as it had been in 1962, and Campbell had to battle to push CN7 to record speeds. On 17 July 1964 he set the record at 403.10 mph (648.73 km/h). The car covered the final third of the measured mile at an average of 429 mph (690 km/h), peaking at over 440 mph as it exited. Campbell considered the result a disappointment given the car's 500 mph design target, but the poor lake surface had made higher speeds impossible.
To celebrate the achievement, Campbell drove CN7 through the streets of Adelaide before a crowd of more than 200,000 people. The car was subsequently displayed widely in Australia and the United Kingdom. In June 1966 it was demonstrated at RAF Debden in Essex; a stand-in driver, Peter Bolton, crashed the car at medium speed, damaging the bodywork and front suspension.
Campbell pressed on with plans for a rocket-powered successor but was killed in January 1967 when his Bluebird K7 jet hydroplane disintegrated during a water-speed record attempt on Coniston Water in England.
CN7 was restored in 1969 and became a permanent exhibit at the National Motor Museum at Beaulieu, England, where it remains on display.