Chamossaire, named after a mountain in Switzerland was sent into training with Richard "Dick" Perryman at his Beaufort House stable in Newmarket.

[4] Restrictions imposed during the Second World War meant that many British racecourses, including Epsom, Doncaster and Ascot were closed and many races were either abandoned or run away from their traditional venues.

In an exceptionally strong renewal of the race he finished fourth of the twenty runners behind Court Martial, Dante and Royal Charger.

In a field of twenty-seven runners he again finished fourth, beaten two lengths, a head and a neck by Dante, Midas and Court Martial.

The race attracted a crowd estimated at 150,000 causing serious congestion on the roads leading to the racecourse: many spectators abandoned their cars and walked the final miles to the course.

Chamossaire took the lead a furlong from the finish and held off the late challenge of King George VI's colt Rising Light to win by two lengths, with Stirling Castle in third place.

The successes of Santa Claus earned Chamossaire the posthumous title of Leading sire in Great Britain and Ireland in 1964.