In 1936 he was slow to find his best form and ran unplaced in both the 2000 Guineas and the Epsom Derby before recording an upset victory in the St Leger at Doncaster Racecourse in September.
[2] Boswell was probably the best horse sired by Lord Derby's stallion Bosworth who finished second in the St Leger in 1929 and won the Ascot Gold Cup in the following year.
[3] Boswell was beaten in the Column Produce Stakes on his three-year-old debut and then finished unplaced behind Lord Astor's Pay Up in the 2000 Guineas at Newmarket.
[6] He took his place in the field for the Derby on 27 May but after a brief effort approaching the straight he faded to finish unplaced as the Aga Khan's Mahmoud won from Taj Akbar and Thankerton.
The closing stages of the race developed into a "most exciting duel" between Fearless Fox and Boswell with the latter gaining the advantage in the final strides to win by three quarters of a length.
[14] Boswell began his third season with a defeat in the Heathcote Stakes and then finished unplaced behind Precipitation in the Ascot Gold Cup, in which he apparently failed to stay the two and a half mile distance.
For his next race he was dropped back in distance for the £9,283 Eclipse Stakes over ten furlongs at Sandown Park Racecourse on 17 July and started at 20/1[9] in a six-runner field headed by Rhodes Scholar.
[16] At Newmarket in August he started 5/4 favourite for the Dullingham Stakes but came home last of the three runners, prompting comments to the effect that Woodward had made a mistake by keeping the horse in training.