While engaged upon a monument in Crosbie churchyard, near
Monkton, in 1827, he attracted the attention of David Auld, a hairdresser in Ayr. Encouraged by Auld, he carved a bust of Burns from a portrait — a copy of the portrait by
Alexander Nasmyth — which hung in the Burns Monument at
Alloway. It confirmed Auld's opinion of Thom's ability, and induced him to advise the sculptor to attempt something more ambitious. It was decided to create statues of Tam O'Shanter and Souter Johnnie, characters from Burns's poem ''
Tam o' Shanter''; Thom, who resided with Auld, set to work on the life-size figures, which were hewn direct from the stone without a preliminary sketch. William Brown, tenant of Trabboch Mill, served as model for Tam; no one could be induced to sit for the Souter, whose face and figure were surreptitiously studied from two cobblers in the neighbourhood of Ayr. They reached London in April 1829, and at once attracted great notice, the critics hailing them as inaugurating a new era in sculpture. Sixteen replicas, it was said, were ordered by private patrons, and reproductions on a smaller scale, but also in stone, were carried out by Thom and his brother. James Thom also produced statues of the landlord and landlady of the poem, which were grouped with the others, and several pieces of a similar class, such as "Old Mortality and his pony", which was conceived in 1830 while reading Scott's novel
Old Mortality on board the packet-boat between Leith and London. A few years later a second exhibition of his work was organised in London, but proved a failure. ==In America==