The group coalesced around the Bentley factory in Cricklewood, north London, at a time when the company needed both financial rescue and competitive credibility. Many members were independently wealthy, drew from military backgrounds, and participated in a wide range of adventurous pursuits. Their commitment to serious racing kept Bentley's reputation alive during periods when the company itself was financially precarious.
The decisive intervention came in 1925, when Woolf Barnato — heir to a fortune accumulated by his father, the South African diamond and gold magnate Barney Barnato — stepped in to save the business. Barnato invested in excess of £100,000 through his finance vehicle Baromans Ltd, paid off existing creditors for £75,000, devalued existing shares to one shilling each, and became chairman, holding 149,500 of the new shares. He continued injecting capital: £35,000 in July 1927, £40,000 in 1928, and £25,000 in 1929, enabling W. O. Bentley to develop successive generations of cars.
The Bentley Boys drew from a strikingly varied cross-section of Edwardian and inter-war society. Core members included Woolf "Babe" Barnato; Dudley Benjafield; Sir Henry "Tim" Birkin; Dale Bourne; Frank Clement; S. C. H. "Sammy" Davis, automotive journalist and sports editor of The Autocar; John Duff; George Duller, a steeplechaser; Clive and Jack Dunfee; Dudley Froy; Baron Andre d'Erlanger; Clive Gallop, an engineer who had designed the overhead camshaft for W. O. Bentley's first 3-litre engine; Prince George Imeretinsky; Glen Kidston, an aviator; Bertie Kensington-Moir; Bernard Rubin, a pearl fishery magnate; and Jean Chassagne, a French racing driver.
The group's defining achievement was four consecutive outright victories at the 24 Hours of Le Mans: 1927, 1928, 1929, and 1930. In 1927, three Bentley 3-Litre cars finished first, fifteenth, and seventeenth. In 1928, a 4½-Litre car driven by Barnato and Bernard Rubin won outright. The 1929 race saw an emphatic 1-2-3-4 sweep, with the Speed Six leading three 4½-Litre cars home. In 1930, a Speed Six took first and second.
Bentley's principal rival was Bugatti, whose lightweight, elegant but fragile cars contrasted markedly with the heavy, durable Bentleys. Bugatti's founder reportedly referred to the British machines as "the world's fastest lorries." Bentley withdrew from motor racing after the 1930 Le Mans, stating that the company had "learned enough about speed and reliability."
One of the most technically contentious episodes of the era involved Sir Henry Birkin and the 4½-Litre Blower Bentley. Birkin developed the supercharged 4½-Litre at Welwyn Garden City in 1929 and produced five racing specials, beginning with Bentley Blower No. 1, optimised for Brooklands. W. O. Bentley himself was vehemently opposed, stating that to supercharge the engine was to "pervert its design and corrupt its performance." However, Birkin had the financial means to purchase 50 4½-Litre cars — capital Bentley Motors urgently needed — so Barnato overruled W. O. Bentley and approved the project. The results bore out W. O. Bentley's scepticism: undoubtedly fast, the Blower Bentleys were chronically unreliable and none ever won a race. Birkin did record a remarkable second place in the 1930 French Grand Prix at Pau in a stripped-down racing Blower, behind Philippe Etancelin's Bugatti Type 35.
In March 1930, Barnato raised the stakes on the emerging fashion for racing the legendary French express, Le Train Bleu. A Rover and its Rover Light Six had recently beaten the train from Cannes to Calais. Barnato wagered £100 that he could better that record with his 6½-litre Bentley Speed Six and, crucially, reach his London club before the train arrived at Calais. Driving on public highways from Cannes to Calais, then by ferry to Dover, and finally on to London, he won the bet.
Barnato drove his H. J. Mulliner-bodied formal saloon in the actual race. Two months later, on 21 May 1930, he took delivery of a different car: a Speed Six with a streamlined fastback "Sportsman Coupe" body by Gurney Nutting. Both cars became known as the Blue Train Bentleys. The Gurney Nutting coupe has frequently been misidentified as the car that raced the train — an error compounded by a well-known painting by Terence Cuneo depicting it in that scenario — but it was delivered two months after the race and never participated. Barnato named it in memory of the event.
The Bentley Boys period established an archetype — the wealthy, courageous amateur gentleman-racer — that influenced British motor sport culture for decades. Their victories at Le Mans gave the marque an endurance-racing pedigree that Bentley continued to trade on long after the golden age ended.
Barnato's personal expenditure on keeping the company operational was substantial, but the Wall Street Crash of 1929 and the resulting Great Depression destroyed the market for Bentley's expensive cars. In July 1931, two mortgage payments fell due that neither the company nor Barnato could meet, and a receiver was appointed. Rolls-Royce, acting through a front entity called British Central Equitable Trust, submitted the winning sealed bid of £125,000 — the true identity of the purchaser unknown even to Bentley himself until the deal was complete. Barnato received £42,000 for his shares, a small fraction of the funds he had invested. He was appointed to the board of the reconstituted Bentley Motors (1931) Ltd in 1934.