Surplice was a dark bay horse with a small white star standing 16.1 hands high,[1] making him an unusually large Thoroughbred for his time.

[3] In 1846, Bentinck decided to concentrate on his political affairs and sold all his racing interests, including the yearling Surplice, to Edward Lloyd-Mostyn for £10,000.

His earnings of £5,550 were the highest for any British two-year-old that season[8] and his performances were sufficient to send him into the winter break regarded as the leading contender for the following year's Derby.

Surplice maintained his position as Derby favourite in early 1848, despite a series of negative rumours which seemed to originate from Lord Clifden's racing manager, Francis Villiers who had a strong financial interest in his stable companion, Loadstone.

Surplice successfully turned back the challenge but had to be ridden hard to hold the late run of Springy Jack and win by a neck.

[9] After the race Benjamin Disraeli was attempting to console Lord George Bentinck who was downhearted at having sold the horse who had won the Derby.

Ridden by Nat Flatman, a late replacement for Jem Robinson,[14] Surplice raced prominently and moved up to challenge the leader Flatcatcher early in the straight.

As a result of his strong autumn form, Surplice was made 3/1 favourite for the Cesarewitch Handicap two weeks later, despite the unfavourably soft ground,[19] but finished unplaced behind The Cur.

[20] Surplice's first run as a four-year-old was intended to be a match race at Newmarket in April in which he was scheduled to concede 35 pounds to Lord Exeter's filly Tophana, but he failed to appear and his owner paid a forfeit.

[24] Later that month he failed to appear for a match race at Newmarket in which he was set to receive sixteen pounds from the six-year-old Royal Hunt Cup winner Collingwood.

At Newmarket on 29 April he was "easily" beaten in a match race over a sprint distance in which he attempted to concede nineteen pounds to a filly called St Rosalia.