The F1 car nobody wanted to drive

British Racing Motors had been founded with the laudable intention of flying the flag at the top level of international motor racing.

But this post-war British engineering showcase spent much of its first decade mired in humiliation.

BRM's first attempt at a Formula 1 car, the Type 15, had been a classic example of engineering over-reach: its complex and temperamental supercharged 1.5-litre V16 engine was just one of its many problems.

Serial late withdrawals from races began to attract scathing editorials in the press, and BRM was at least partially culpable for world championship grands prix being run for F2 entries only between 1952 and 1953 as race promoters across Europe despaired of seeing any worthy opposition to Ferrari.

New F1 rules made the Type 15 obsolete before it could be developed into a reliably competitive car, but this did not persuade BRM's senior engineers to temper all of their ambitions when they began to draw its successor.

The P25 would have all the makings of a fast F1 car but it would take years of development to debug it - by which time the rear-engined revolution would make it irrelevant as well as obsolete.

The Type 15 project was financially ruinous and Sir Alfred Owen, the industrialist who was one of the team's key investors, stepped in to rescue BRM in October 1952.

That enabled development of the Type 15 to proceed so it could race in sundry Formula Libre events, though BRM would have been better served by focusing on the new 2.5-litre unsupercharged F1 formula coming in 1954. It continued to live up to its reputation as a shambles, failing to finish the P25 in time for that season and having to field a Maserati 250F instead.

In its first incarnation, the P25 was innovative in many ways, using an unusual form of semi-monocoque chassis construction in which the bodywork was riveted in place and acted as a partially stressed element, augmenting the steel tubing beneath.

It featured disc brakes all round, with a single one at the back mounted to a four-speed gearbox on the transaxle.

Co-founder and chief engineer Peter Berthon did take the lessons of the Type 15 on board in the engine bay, selecting a concept proposed by consultant engineer Stuart Tresilian: a four-cylinder twin-camshaft with an 'oversquare' design in which the bore diameter was wider than the stroke length.

This theoretically yields greater torque and enables larger valve widths, particularly in this case since Berthon decided against Tresilian's initial four-valve-per-cylinder concept.

Beyond that, Berthon wilfully disregarded a key flaw of the Type 15 by equipping the P25 with, in effect, the same suspension concept: double wishbones at the front with oleopneumatic struts taking responsibility for both springing and damping, with a De Dion axle at the rear hanging from a transverse leaf spring.

The P25 wasn't ready to race until September 1955, 19 months after the 2.5-litre formula came into effect.

Even then it missed its first scheduled event, a non-championship race at Aintree, when Peter Collins crashed after a broken seal coated the rear wheels in oil.

BRM signed Mike Hawthorn and Tony Brooks for 1956 but the non-championship races had revealed serious flaws with the P25, forcing the team to run its 250F in the opening round in Argentina.

Vibrations from the engine played havoc with the oil system and the large valves were prone to damage, which led BRM to withdraw from Monaco, where the P25 was supposed to make its championship debut.

Brooks recorded in his diary the cars had the wrong gear ratios for the course and insufficient steering lock to get around the hairpins, anyway.

At Silverstone for the British Grand Prix - where Raymond Mays had teased spectators with a demo of the Type 15 back at the first world championship round in 1950 - BRM went all-in with a third entry for Ron Flockhart.

All the P25s had reinforced valves and the race started well as Hawthorn and Brooks roared past Stirling Moss's Maserati and Juan Manuel Fangio's Ferrari to run 1-2.

But then disaster: Flockhart stopped when his engine's timing gear ate itself, Brooks broke his jaw in a severe crash when his throttle stuck open, and Hawthorn's gearbox failed. Owen declared that the P25 shouldn't be raced again until it could complete a distance without breaking down.

Hawthorn - who said the car had tripled his laundry bills - and Brooks quit at the end of the season.

Despite a strengthened chassis and longer wheelbase for 1957, further issues with the handling and brakes manifested themselves in the form of terrifying moments for Flockhart and new recruit Roy Salvadori.

By Monaco, Colin Chapman had been drafted in to consult and one of his first proposals was to junk the suspension arrangement in favour of coil-over shock absorbers. Salvadori had already decided to quit and, when Flockhart was injured in a shunt at Rouen, BRM suffered further humiliation when no top-rank driver was willing to sit in a P25 for the British Grand Prix.

Although the engine was redesigned for 1958 with a five-bearing crankshaft to smooth out the vibrations, F1's shift from alcohol-based fuels to Avgas brought cooling problems that masked improvements elsewhere - and which weren't properly understood or fixed until 1959.

A new chassis, built up around a spaceframe with curved undertrays acting as partially stressed elements (enabling the bodywork, previously riveted to the frame, to be removed more easily), plus revisions to the front suspension geometry, transformed the handling.

Cooling-related unreliability blighted 1958 but the following season the P25 came good, enabling Joakim Bonnier to qualify on pole for the Dutch GP and win, having been among the frontrunners throughout.

It was BRM's first world championship victory.

Elsewhere the rear brake continued to be problematic, and the more nimble and better-balanced rear-engined Cooper was in the ascendant in the hands of Jack Brabham.

Eventually BRM broke up all bar one of the P25s to cobble together a mid-engined car, designated the P48. The surviving example - Bonnier's Dutch GP winner, chassis 258 - is pictured in this feature.

RACE RECORD

Starts 54
Wins 1
Poles 1
Fastest laps 1
Podiums 3
Points 36

SPECIFICATION

Chassis Steel ladder/spaceframe (1958-onwards) semi-monocoque
Suspension Double wishbones, oleopneumatic struts/coil springs and telescopic dampers (f), De Dion axle with transverse leaf spring/coil springs and telescopic dampers (r)
Engine BRM 25 inline 4
Engine capacity 2491cc
Power 275bhp@8,000rpm
Gearbox Four-speed manual
Tyres Dunlop
Weight 690kg
Notable drivers Peter Collins (non-championship), Mike Hawthorn, Tony Brooks, Ron Flockhart, Roy Salvadori, Jean Behra, Harry Schell, Stirling Moss, Joakim Bonnier, Hans Herrmann, Graham Hill, Maurice Trintignant