Thomas had a short, dramatic, though unsuccessful career in the Army, beginning as a cornet in the 3rd Light Dragoons in 1776. Then he was a Lieutenant in a marching regiment, the 29th, later he was in the 60th Foot, finally, no doubt for the better pay, joining the 6th West Indian Regiment, in 1799, the destination of many who lived joyously beyond their means.

Crockett, the novelist, portrays a member of the family as "Roystering Tom of the Isle" and "ten tass Lidderdale", Tom of the Isle being, no doubt, the last effective laird of our name who lies in Gata. Dr. Robert, who charmingly described Margaret, said he had not come across hard drinking members of the family; very different were those he had known. But he had not met Thomas. A drunkard, no, convivial, yes. Good-looking too, for his granddaughter Azile, speaking from tradition told a romantic story about her grandfather, passing through Ludlow with his regiment, being struck by the sparkling eyes and fascinating appearance of a young lady at a window, equally attracted by the dashing young officer. Apparently love at first sight, and so followed the marriage of Lieutenant Tom Lidderdale to Miss Eliza Cropper. The marriage was not very fortunate for her as Thomas had suffered one shipwreck which had impaired his health, and at the end he suffered another which will be told in the words of his son Thomas Robertson.

On the walls of the family burial enclosure in Galtway Kirkyard are tablets to the memory of the following members of the family mostly buried there.

- JOHN LIDDERDALE of Castle Milk, son of David of Torrs, died 10th August 1777, aged 64.
- THOMAS youngest son of John Lidderdale of Castle Milk, Dumfries, who died at Ambergis Bay [Ambergris Cay] of Honduras, 28th December 1777 [should be 1799] aged 39.
- THOMAS ROBERTSON who died at Appleby, Westmorland, 15th May 1852, aged 67 and his only surviving son.

Source: Robert Halliday Lidderdale, An Account of the Lowland Scots Family of Lidderdale, 1950.

We have now to refer to Thomas, the youngest surviving son of John Lidderdale of Castlemilk, Dumfries-shire. He joined the 3rd (King's Own) Light Dragoons as a cornet in 1776; became a lieutenant in the 89th Regiment; and a captain in the 60th Regiment in 1799. The same year he exchanged into the 6th West India Regiment. He married, 20th March 1783, Eliza, daughter of - Cropper of Ludlow, and had issue:

    Thomas Robertson, born 24th March 1785, died 16th May 1852.
    Sophia Matilda Eliza.
    Anna Mariana Barbara.

He obtained for his son an ensign's commission in the 6th W. I. Regiment. Both were shipwrecked in the Bay of Honduras. Captain Lidderdale died and was buried in the sand on the shore. His son, twice again wrecked, became broken in health, and was placed on half-pay. Thomas Robertson married, 16th June 1823, Anne (born 2nd June 1787), daughter of William Sadler of Bolton Hall. She (died 4th November 1865) had issue,

    John, died in infancy.
    Thomas William.
    Amelia Eleanora

Source: P.H. McKerlie, History of the Lands and Their Owners in Galloway, 1878.