[9] He contributed a chapter exploring the 'social democratisation of the SNP' to a book on post-devolution politics called Breaking Up Britain – Four Nations After a Union, published in 2009 by Lawrence & Wishart.

[4] In 2001, he unsuccessfully contested the Tweeddale, Ettrick and Lauderdale constituency, a safe seat for the Liberal Democrats in which Thomson came fourth with 4,108 votes (12.4%).

[4] In 2010, he stood in Gordon: the Liberal Democrat Malcolm Bruce retained his seat, but Thomson took the SNP into second place.

"[13] He narrowly won the seat from the Conservative incumbent Colin Clark, with a slim majority of 819 votes (1.4%).

In 2023, when questioned about Inverurie's largest medical practice not renewing its NHS contract due to recruitment issues, Thomson said he "would do everything" he could "to attract doctors to the constituency".