As soon as the first motorcars were built, the race was on to make them faster. In the 1920s and 30s, two car companies, Bentley and Mercedes-Benz, dominated the world of motor racing and speed was to become a matter of national pride.

Walter Owen Bentley, known as WO, served an apprenticeship as a railway engineer. In 1912, he joined his brother selling cars in the UK made by the French car company DFP. During the First World War, WO developed his engineering skills. The skills were soon put to use as his new combustion engines were to power the RAF's Sopwith Camel fighter biplanes. He had worked at improving DFP's cars but WO's goal was to use his experience to build his own motorcars and in 1919 he moved closer, forming Bentley Motors Ltd. In 1920, WO produced the first of his 3-litre Bentleys.

By the early 1920s, his powerful cars were doing well at the established Brooklands racetrack in Surrey. They were driven by a set of wealthy young men, who came to be known as the Bentley Boys.

The Bentley Boys dominated the British racing scene and gained international fame. They were united by their immense wealth, fast living and most importantly their love of speed. They included the diamond mine owner Woolf Barnato, Sir Henry 'Tim' Birkin, Harley street physician John Benjafield, motor sport journalist Sammy Davis and ex-submarine officer Glen Kidstone.

In 1923, a new competition was introduced which would test these men to the limit. The 24-hour endurance race at Le Mans in France would run production vehicles over a 10-mile circuit on public roads. One of the Bentley racers, John Duff, was thrilled by the challenge and contacted WO, eager to take a Bentley into the race. WO wasn't keen but eventually loaned Duff his test driver, Frank Clement, as a co-driver. At the last minute, WO decided to attend Le Mans himself – it changed his life forever. Duff came fourth and gained the fastest average lap time of 67mph. WO was ecstatic and saw Le Mans as a vehicle for flying the British and Bentley flags. In 1927 and 1928, the Bentley Boys wiped the board at the annual Le Mans. The winning Bentley was guest of honour at the celebratory dinner at the Savoy, London.

But by the end of the 1920s, one company was beginning to challenge the might of Bentley.

In 1901, German motorcar company Daimler renamed itself Mercedes to appeal to the anti-German French market. By 1914, Mercedes had begun to break into the racing world, winning 1st, 2nd and 3rd places at the French Grand Prix. By the mid 1920s, they had introduced a new series of racing car with a supercharged 4-litre engine. In 1926 Mercedes joined forces with the other major German car company, Benz, forming Mercedes-Benz. In that same year, Bentley would get a glimpse of the future when Mercedes-Benz won the German Grand Prix with the 22-year-old driver, Rudolf Carraciola.

Mercedes-Benz had seen the way ahead with the new supercharged engines, but Bentley wanted nothing to do with them. Not all the Bentley drivers thought this way though and Tim Birkin decided that he would supercharge his Bentley. In September 1929, Bentley would finally be put to the test as they went head-to-head with Mercedes-Benz at Ards in Ireland.

The weather was poor and the Bentleys suffered in the driving rain. The way was clear for Carraciola, who drove his Mercedes-Benz to victory. Birkin came in 11th. Bentley had suffered its first blow, but later in the year, they swept the board at the 500-mile Brooklands race, albeit without a Mercedes-Benz challenger.

By 1930, economic depression was beginning to sweep through Europe and the luxury automobile industry was feeling the pinch. Only 18 cars entered the Le Mans race. The official Bentley team entered three 6.5-litre Speed Sixes, whilst Birkin entered two of his own 4.5-litre supercharged Bentleys. At the start of the race, Mercedes-Benz dominated with Carraciola in the lead. Bentley pushed the Mercedes-Benz car harder and harder. It was a good tactic since the supercharger performed best in short bursts. Around midnight, Carraciola had to pull out, although he completed the fastest lap. Neither of Birkin's cars finished the race, but Barnato came in first, completing his Le Mans hat trick. It was Bentley's finest hour but by now the depression had taken its toll and in 1931 Bentley was taken over by Rolls Royce.

Mercedes-Benz was also hit hard by the depression, but their fortunes changed when Hitler came to power. He saw racing success as a way of promoting Germanic superiority. With state backing, Mercedes-Benz turned away from endurance races like Le Mans and concentrated on Grand Prix racing. They went from strength to strength. In 1937, Mercedes-Benz released the W125, a sprightly racing car that set the standard for its time.

Without Mercedes-Benz and Bentley, Le Mans was now dominated by the Italian Alfa Romeos which received state backing from Mussolini. They would win the race four years in a row, but Bentley's legendary five wins at Le Mans in the 1920s had ensured their place in racing history.