The Coldstream Guards is the oldest continuously serving regular regiment in the British Army. As part of the Household Division, one of its principal roles is the protection of the monarchy; due to this, it often participates in state ceremonial occasions. The Regiment has consistently provided formations on deployments around the world and has fought in the majority of the major conflicts in which the British Army has been engaged.

The Regiment has been in continuous service and has never been amalgamated. It was formed in 1650 as 'Monck's Regiment of Foot' and was then renamed the 'Lord General's Regiment of Foot Guards' after the Restoration in 1660. With George Monck's death in 1670 it was again renamed the 'Coldstream Regiment of Foot Guards' after the location in Scotland from which it marched to help restore the monarchy in 1660. Its name was again changed to the 'Coldstream Guards' in 1855 and this is still its present title.

Today, the Regiment consists of: Regimental Headquarters, a single battalion (1st Battalion), an independent incremental company (Number 7 Company, maintaining the customs and traditions, as well as carrying the Colours of 2nd Battalion), a Regimental Band, a reserve company (Number 17 Company) and individuals at training establishments and other extra regimental employment.

The origin of the Coldstream Guards lies in the English Civil War when Oliver Cromwell gave Colonel George Monck permission to form his own regiment as part of the New Model Army. Monck took men from the regiments of George Fenwick and Sir Arthur Haselrig, five companies each, and on 13 August 1650 formed Monck's Regiment of Foot. Less than two weeks later, this force took part in the Battle of Dunbar, at which the Roundheads defeated the forces of Charles Stuart.

After Richard Cromwell's abdication, Monck gave his support to the Stuarts, and on 1 January 1660 he crossed the River Tweed into England at the village of Coldstream, from where he made a five-week march to London. He arrived in London on 2 February and helped in the Restoration of the monarchy. For his help, Monck was given the Order of the Garter and his regiment was assigned to keep order in London. However, the new parliament soon ordered his regiment to be disbanded along with all of the other regiments of the New Model Army.

Before that could happen, Parliament was forced to rely on the help of the regiment against the rebellion by the Fifth Monarchists led by Thomas Venner on 6 January 1661. The regiment defeated the rebels and on 14 February the men of the regiment symbolically laid down their arms as part of the New Model Army and were immediately ordered to take them up again as a royal regiment of The Lord General's Regiment of Foot Guards, a part of the Household Troops.

The regiment was placed as the second senior regiment of Household Troops, as it entered the service of the Crown after the 1st Regiment of Foot Guards, but it answered to that by adopting the motto Nulli Secundus (Second to None) as the regiment is older than the senior regiment. The regiment always stands on the left of the line when on parade with the rest of the Foot Guards, so standing "second to none". When Monck died in 1670, the Earl of Craven took command of the regiment and it adopted a new name, the Coldstream Regiment of Foot Guards.

The regiment saw active service in Flanders and in the Monmouth Rebellion, including the decisive Battle of Sedgemoor in 1685. It fought in the Battle of Walcourt in 1689, the Battle of Landen and the Siege of Namur.