The Britannian Infantry are the conventional foot soldiers of the Britannian Ground Force. Britannian foot-soldiers are typically outfitted with assault rifles, pistols, body armour, and helmets with electronic visors. They are well trained and very loyal to the Empire. They were also present during Emperor Lelouch's regime. Britannian infantry seemed to be armed with a longer barrelled rifle during the Invasion of Japan. However, when Knightmare Frames became the main arm of the Britannian army, the infantry switched to the short barrelled assult rifle commonly seen in the series. Since the introduction of the Knightmares, the infantry seem to be deploy as bodyguards, ground support, shock troops for infiltrations and death squads. They are shown to be very ruthless and efficient giving little to no regards to civillians or enemies. They are also trained to fight enemy knightmares as a squad of St. Michael knights took down an EU drone by using a slinged explosive to destory its leg before proceeding to fire on the cockpit.
The Britannian Combat Armour is considered to be the most advanced in the world. The armour consist of Gray Jumpsuit, Flak Vest, two Pauldron and a Helmet. The helmet is the most technologically-advanced part of the armour, incorporating a communicator, gas mask, and a highly sophisticated combat sensor suite.
The latter function is only shown in Episode 1 of R1, when Suzaku finds the truck containing CC's capsule and Lelouch. The visor zooms in on the capsule as the door opens, then detects and points out Lelouch. This suggests motion detection, but it can also identify an unmoving human.
The armour itself is highly protective, as evidenced by Episode 1 of R1. Suzaku is shot with a handgun at point-blank range, with the gun being shown to be aimed at a gap in the armour between the back plate and his belt. The jumpsuit nevertheless slowed the bullet enough for Suzaku's fob-watch to deflect it with only a cracked face, though the force was still enough to seriously injure him and render him unconscious.
The combat armour worn by the Knights of St. Michael have a red marking on their chests.
When they're not in their armour, army officers and soldiers are seen to be wearing blue uniforms. The barrack dress uniform consist of the grey jump suit and blue uniforms. St. Michael Knights instead wear red uniforms.