He was given overall command of the expedition to Concord, which consisted of twenty one companies of Light infantry and grenadiers totaling around 700 men, whose orders were to search the town for contraband supplies and weapons, particularly artillery.

General Thomas Gage believed that the mission required a force larger than a regiment but smaller than a brigade and so assembled it by taking individual companies from the various units in Boston.

After being alerted to the possibility that there was opposition on the road, Smith ordered some light infantry to move forward while he stayed with the main body of the expedition, thus he was not present at the skirmish in Lexington.

More and more of Smith's officers were killed or wounded, hampering his attempts to maintain control, and his men finally lost unit cohesion and hurried onward in a general mass.

[2] His column was extremely hard-pressed and close to total collapse but managed to reach the comparative safety of Lexington where a brigade of British reinforcements under General Percy had arrived.

Perceptions of him have altered over time as the battles have been re-examined – moving away from initial portrayals that tended to paint him and his officers having deliberately set out with the intention of killing colonial militia.

While the first reports of the fight were the catalyst for the outbreak of the war, tipping a number of colonies into open rebellion, its importance as a historical event only really grew in significance in the century after American independence was granted by the 1783 Peace of Paris.

[citation needed] The narrative of the fight on Lexington Green gradually changed from one of an unprovoked massacre of loyal citizens by the redcoats, into a more even-handed and inevitable clash between the two forces which was the inescapable consequence of an American desire for nationhood.

Since the Second World War, many accounts have disregarded this interpretation, and emphasized the more ambiguous nature of the situation in Massachusetts in Spring 1775 when the colonists still considered themselves British and very few advocated outright independence.

[citation needed] Considerable confusion still remains about what exactly happened at Lexington Green when the British regulars and militiamen drew up opposite each other with a number of different versions of who fired the first shot advanced by various accounts and historians.

[citation needed] While Smith has often been attacked for his decisions, he has also been praised for bringing his column through repeated ambushes during the retreat from Concord to the safety of Percy's reinforcements without entirely disintegrating.

John Galvin who wrote a history of the Lexington and Concord fighting, observed that "Smith, unfortunately, could match this steadiness with an equal slowness and lack of imagination, a fact that has received more than enough attention over the years, perhaps obscuring his coolness and courage".