The genesis of the Type 15 lay in the pre-war ambitions of Raymond Mays, a patriotic British racing driver who had long wanted to see a truly competitive British Grand Prix car. In early 1939, after the wealthy backer of English Racing Automobiles withdrew his funding, Mays and ERA engineer Peter Berthon founded Automobile Developments Ltd with the intention of building a world-beating British Grand Prix car along the lines of Mercedes-Benz and Auto Union. Throughout the Second World War the concept developed in the minds of its founders. Berthon fixed on the idea of a supercharged 135-degree V16 engine, partly for technical reasons and partly, it has been suggested, to give the project a spectacular selling point when approaching potential industrial sponsors.
On 25 April 1947 the British Motor Racing Research Trust was formally constituted. More than three hundred British companies contributed, including Lucas, Girling, Rolls-Royce, Vandervell, Rubery Owen, David Brown and Standard Motors. The car ultimately cost an astonishing £200,000 (equivalent to approximately £8 million in 2023), at least twenty times more expensive than any competitor.
The V16 engine displaced 1.5 litres and was a 135-degree configuration, designed to produce 500 bhp at 12,000 rpm. Rather than the conventional Roots-type supercharger used by most competitors, it employed twin centrifugal superchargers developed by Rolls-Royce based on units from the Merlin aero engine. This arrangement produced enormous power at high revs but very little lower in the rev range, forcing drivers to work within a narrow power band throughout every race.
The chassis was a conventional ladder structure with pairs of tubes running down each flank linked by welded sheet metal and cross members. Suspension drew on captured German technology, using Auto Union-derived trailing arms at the front and Mercedes-inspired de Dion radius arms at the rear. The Type 15 rode unusually low compared with other Formula One cars of the time, an intentional choice to keep the centre of gravity as low as possible. Steering was by recirculating ball and nut, despite calls from Stirling Moss and others for rack-and-pinion. Braking was initially by drum with three shoes per corner, but late in 1951 the team fitted disc brakes, marking the first use of disc brakes on a Formula One car.
The first car was not ready to run until December 1949, and by the time the new World Championship opened in 1950 BRM was not ready to race. Mays gave the Type 15 a demonstration run at the 1950 British Grand Prix at Silverstone, generating public enthusiasm and a flood of donations. The team then targeted the International Trophy at Silverstone as the car's race debut. The much-anticipated appearance ended in humiliation: of the two cars entered, only Raymond Sommer's was fit to start, and it moved only a few inches from the grid before a drive shaft failure stranded it. Loud booing greeted the car as it was wheeled away and spectators mockingly threw pennies at it.
The next outing, at Goodwood, proved more encouraging. Reg Parnell won the Woodcote Cup and the Goodwood Trophy on the same day. But the cold conditions had concealed overheating problems that would recur throughout the car's early career.
For 1951 two improved cars entered the British Grand Prix at Silverstone. The exhaust routing within the bodywork created unbearable heat in the cockpit during the full race distance, and drivers needed burns dressings applied during pit stops to protect their arms. Parnell and Walker struggled on to the finish, coming home fifth and seventh, several laps behind the winning Ferrari of José Froilán González. At Monza, early indications in practice were better but an inspection of the gearboxes revealed dangerous wear and BRM withdrew both cars before the race on safety grounds.
At the start of 1952 the FIA decreed that World Championship Grands Prix would run to Formula Two regulations for 1952 and 1953, in the absence of Alfa Romeo and with Ferrari dominating the field. The Type 15 was not eligible for F2 and BRM had to content themselves with non-championship Formula One events, Formula Libre races and minor British meetings.
This period produced some success. Juan Manuel Fangio and González drove for BRM, and the team won at various venues including Goodwood and Charterhall. Stirling Moss, who also drove the car, was not kind in his assessment, describing the Type 15 as "without doubt the worst car I ever raced — it was a disgrace."
Under new ownership by Alfred Owen from 1952, the Type 15 finally began to realise some of its potential in 1953. Wharton won three consecutive races at Snetterton and Charterhall, and the team performed consistently throughout the year. In 1954 an updated variant, the P30, was built with a reduction of over 200 lb in weight and a shorter wheelbase. The two P30s, driven by Wharton and Ron Flockhart, won five of the first six races they entered in 1954. By 1955 the car's racing life was essentially over as BRM turned its attention toward re-entering the World Championship with new machinery.
Four Type 15s were produced. One was written off in a collision during the Glover Trophy; another that crashed at Albi was used as the basis for one of the two P30s. The two surviving Type 15s are preserved in Britain: one at the National Motor Museum at Beaulieu and one at the Donington Grand Prix Exhibition in its original light green paint alongside a P30 and a cutaway V16 engine. The fourth surviving car, a P30, was at one time owned by Pink Floyd drummer Nick Mason before passing to Bernie Ecclestone. The cars appear periodically at historic racing events including the Goodwood Festival of Speed.
The BRM Type 15 remains one of the most compelling stories in British motorsport: an extraordinary technical achievement that was consistently beaten by circumstance, regulation changes and its own complexity. The V16 engine's distinctive screaming exhaust note made it a favourite with spectators even when it was failing to finish, and the project inspired enough national pride to survive years of embarrassment before eventually delivering competitive results when the opportunity for championship glory had already passed.