The 1862 Derby was memorable due to the large field (34 horses), the winner being ridden by a 16-year-old stable boy and Caractacus' near disqualification for an underweight jockey and a false start.

Blenkiron frequently observed the mare's ability to maneuver obstacles: she would "canter as hard as she [could] go as straight as a line to the trough and stop dead within two yards of it.

[2] Caractacus was described as a bay colt that stood 15.1 hands high, with a “light” neck, fine shoulders, good girth and sound feet.

[4] He had a “corky” personality and possessed refined movement, leading him to be described as a “slashing goer.”[2] As a yearling, Caractacus was bought for 250 guineas by the trainer William Day, acting on behalf of a London publican named Charles Snewing who also was a veterinary surgeon.

In spring 1861, the two-year-old colt was moved to a stable at Harpenden in Hertfordshire, where his training was managed by Robert "Bob" Smith.

[5] Allegedly, the colt was named 'Caractacus' because Snewing had admired a statue of the British chieftain Caratacus bound in chains at the 1851 Exhibition.

[8] He finished fifth out of a field of eight horses behind Turn of Luck while carrying 110 pounds, and he was jockeyed by a teenage stable boy named John Parsons.

Caractacus secured another second-place finish in the Newmarket Biennial Stakes, losing by two lengths to Joseph Hawley's Sir Rollo.

[11] Consequently, Snewing's stable boy John Parsons, thought to be around 16 years old at the time,[10][12] rode Caractacus as he had done in three of the horse's previous starts.

[6] The Marquis's jockey, Ashmall, attempted to make all the running and turned into the straight with a clear lead, but several challengers emerged, most notably Buckstone and Caractacus.

"[6][11] An objection was also raised by Lord Stamford, the owner of a colt named Ensign, that Caractacus and the majority of the field had made false starts and should all be disqualified.

He was entered for the 1862 St. Leger Stakes, but he injured both suspensory ligaments in his front legs shortly before the running and was permanently retired from racing.