Born in Oatlands, Surrey, Abecassis was educated at Clifton College. He began circuit racing in 1935 in a modified Austin Seven known as "The Einsitzer." After taking 1937 as a year away from the track, he acquired an Alta and made a name for himself in English national racing during the 1938 and 1939 seasons. On 3 July 1938, Abecassis broke the Prescott Hill Climb record with a climb of 47.85 seconds in his supercharged 1½-litre Alta. At one point he also held the Campbell circuit lap record at Brooklands at 72.61 miles per hour (116.85 km/h).
In 1939, he won the Imperial Trophy Formula Libre race at Crystal Palace, driving his Alta. He defeated Prince Bira in the E.R.A. known as Romulus during a wet race — described as "the only time it was beaten by a 1,500 cc (92 cu in) car in the British Isles."
When World War II broke out, Abecassis joined the Royal Air Force Volunteer Reserves. He became an experienced pilot and a member of the secret "Moon Squadrons," ferrying agents in and out of occupied Europe using specially-modified Halifax and Stirling aircraft. He was awarded the Distinguished Flying Cross and mentioned in dispatches, with a citation noting his "keenness and enthusiasm" as a flying instructor and Deputy Flight Commander at an Operational Training Unit. He achieved the rank of squadron leader and remained in the RAF Volunteer Reserves until his discharge in 1953.
Abecassis returned to racing in 1946, winning a race at Gransden Lodge in a road-going 3.3-litre Bugatti. In 1947, he finished second in the Swedish Grand Prix, held on a frozen lake at Vallentuna, driving an E.R.A. The following year he finished second to Bob Gerard in the Jersey International Road Race.
During this period, Abecassis became a partner with John Heath in Hersham and Walton Motors Ltd. (HWM) in Walton-on-Thames. Building on his pre-war association with the Alta marque, Abecassis and HWM assisted in the development of the Alta GP car, designed for the newly introduced Formula One regulations. When this enterprise failed, Abecassis and Heath began constructing their own cars under the HWM banner, retaining Alta engines.
HWM initially competed in Formula Two, but the cars became eligible for Grand Prix events when the World Championship adopted Formula Two regulations in 1952. Abecassis raced in his only two Formula One World Championship Grands Prix in 1951 and 1952 at the Swiss Grand Prix, held at the Bremgarten circuit. During their prime, HWM employed future stars Stirling Moss and Peter Collins, and Belgian driver Johnny Claes scored their first victory at the Grand Prix des Frontières at a street circuit in Chimay, Belgium. Lance Macklin gave the team a notable win at the 1952 International Trophy at Silverstone. A later attempt to use a 2.5-litre Alta engine for Formula One in 1954 was not successful, and HWM cars only contested two further Grand Prix events after 1953.
Abecassis found significant success in sports car racing. Driving for Aston Martin, he won his class at the 1950 24 Hours of Le Mans sharing a DB2 with Lance Macklin, and finished second in the 1953 12 Hours of Sebring partnered by Reg Parnell. In 1953, he constructed a Jaguar straight-6-powered HWM sports car for his personal use, which he successfully contested in national British races until 1956. In the 1955 Mille Miglia, he drove a red Austin Healey 100S to 11th place overall, recording speeds in the final "Rome section" described as close to those of Stirling Moss with the Mercedes SLR.
Following the death of John Heath during the 1956 Mille Miglia, Abecassis retired from racing to manage HWM operations. He became the Facel Vega importer for Britain. His motor industry connections were aided by his marriage to Angela, daughter of Aston Martin chairman Sir David Brown. He died aged 78 in Ibstone, near High Wycombe, Buckinghamshire.
In September 2010, his son David Abecassis published a biography under the title A Passion for Speed. His grandson Jonathan Abecassis competes in the Fifties Sports Car Racing Club ("FISCAR") series, driving an Austin Healey 100/4.
This article is based solely on the supplied corpus. No external sources were consulted; claims that could not be substantiated against the corpus were omitted under the drop-the-claim rule.