The 18th century British soldier was dressed in red long before Wellington. Here is how the pattern was built.
Quick answer. British 18th century infantry wore scarlet or madder dyed wool coats with regimental facings in buff, yellow, blue, green or other colours, worn with white or buff waistcoats, white breeches, long gaiters and a tricorne hat. The pattern evolved from the loose cut of 1700 through the regulation issue of 1751 to the shorter cut of the Revolution era. Cavalry wore similar colours in different cut, with heavy boots and larger hats.
The Marlborough era (1700 to 1715)
British soldiers under Marlborough wore a loose cut red coat with large cuffs turned back to show the facing colour, long broad lapels, no collar, and no particular regimental uniformity across the army. The waistcoat was a long sleeved garment underneath, usually in the regimental facing colour. Trousers were white or buff knee breeches. The tricorne hat was already the standard headdress, cocked up on three sides with a hat band and sometimes a feather or lace trim.
The red colour was chosen for cost (madder was cheap) and visibility, not for the mythical reason of hiding bloodstains. The dye was variable: some regiments wore brick red, others nearly orange, others closer to crimson. Standardisation came only in the second half of the century.
The 1751 Clothing Warrant
George II's Clothing Warrant of 1751 was the first great standardisation of British army dress. The warrant specified cut, cloth quality, lace pattern and facings for every infantry regiment. The coat became more fitted with a smaller cuff and a proper collar. Regimental lace pattern was fixed: a thin coloured line (the regimental 'worm') ran through the white or yellow lace at the edges of the coat and buttonholes, which allowed trained observers to identify the regiment at close range. Officers' coats were cut more finely and used metallic lace.
Breeches were white doeskin or linen, held above the knee. Below the knee came long black linen or canvas gaiters that buttoned up the outside of the leg and reached above the knee. In winter, dark wool overalls could be worn in place of gaiters.
The Seven Years War (1756 to 1763)
British infantry served from Hanover to Quebec during the Seven Years War, which exposed the 1751 pattern to harder service than parade dress had anticipated. Light infantry companies, raised to counter French skirmishers and Native American irregulars in North America, received a cut down version: shorter coat, no lace, round hat instead of tricorne. The experiment of cutting the uniform for actual campaign use began here and would influence all later British patterns.
The American Revolution (1775 to 1783)
By 1775 the British infantry wore a shorter coat, often with lapels buttoned back permanently to show the facing colour. The tricorne was giving way to the lighter round hat or the shortened cocked hat. In North America many regiments cut down their uniforms further still: the famous short jackets, cropped tricornes with brims cut back, and more practical trousers. These field modifications were tolerated by officers and gradually became semi official.
British cavalry during the Revolution wore heavy riding coats, often blue for the dragoons rather than red. The hat was a plumed cocked bicorne. Boots were long leather riding boots to the knee. The Tarleton helmet, named after the famous British Legion commander, appeared toward the end of the war.
The move to the coatee
By the end of the 1790s the long tailed coat was being replaced by the shorter coatee, which would carry the British army into the Napoleonic Wars. The tricorne was replaced by the cylindrical shako or stovepipe from 1800. The facings and lace system of 1751 remained, which is why Napoleonic British regiments can still be identified by the same codes. The 18th century British soldier's dress ended essentially in 1800, as a different silhouette replaced it.
Common questions
What was the 1751 Clothing Warrant?
The first great standardisation of British army uniform. Issued under George II, it specified cut, cloth, lace pattern and facings for every infantry regiment.
Why were they called redcoats?
The coat was red because madder was the cheapest reliable red dye in 17th century England. The colour stuck through the 18th century and defined British dress until khaki took over around 1900.
What is a facing?
The lining of the cuffs, lapels and turnbacks of a coat, shown in a different colour from the main coat. Each regiment had its own facing colour, which was its primary identifier.
Did soldiers really wear tricornes?
Yes, throughout most of the 18th century. The tricorne gave way to the round hat and shako toward the end of the century.
What is a coatee?
A short tailed coat, cut to the waist in front with short tails at the back. The coatee replaced the long tailed 18th century coat around 1800.