During the First World War the British Armed Forces was enlarged to many times its peacetime strength. This was done mainly by adding new battalions to existing regiments (the King's Royal Rifles raised a total of 26 battalions). Although sometimes identified by shoulder titles, generally the new battalions could not be identified from appearance. Consequently, the units in this list have been assembled considering only those as having a uniquely different cap badge.
Although men of the Royal Navy served on land in many areas throughout the world, the units listed below served as an infantry division in Gallipoli, Belgium and France (the 63rd (Royal Naval) Division).
1st (Drake) Battalion2nd (Hawke) Battalion3rd (Benbow) Battalion4th (Collingwood) Battalion5th (Nelson) Battalion6th (Howe) Battalion7th (Hood) Battalion8th (Anson) Battalion9th (Chatham) Battalion RMLI10th (Portsmouth) Battalion RMLI11th (Plymouth) Battalion RMLI12th (Deal) Battalion RMLI9th (Machine Gun) BattalionRoyal Marine ArtilleryRoyal Marine Laour CorpsRoyal Naval Air Service Armoured Car SectionRoyal Naval Air ServiceThe cavalry consisted of Guards (Household Cavalry), Dragoon Guards, Dragoons, Hussars and Lancers. The volunteer cavalry was the Yeomanry.
1st Life Guards2nd Life GuardsRoyal Horse Guards1st (King's) Dragoon Guards2nd Dragoon Guards (Queen's Bays)3rd (Prince of Wales's) Dragoon Guards4th (Royal Irish) Dragoon Guards5th (Princess Charlotte of Wales's) Dragoon Guards6th Dragoon Guards (Carabiniers)7th (Princess Royal's) Dragoon Guards1st (Royal) Dragoons2nd Dragoons (Royal Scots Greys)3rd (King's Own) Hussars4th (Queen's Own) Hussars5th (Royal Irish) Lancers6th (Inniskilling) Dragoons7th (Queen's Own) Hussars8th (King's Royal Irish) Hussars9th (Queen's Royal) Lancers10th (Prince of Wales's Own Royal) Hussars11th (Prince Albert's Own) Hussars12th (Prince of Wales's Royal) Lancers13th Hussars14th (King's) Hussars15th (The King's) Hussars16th (The Queen's) Lancers17th (Duke of Cambridge's Own) Lancers18th (Queen Mary's Own) Royal Hussars19th (Queen Alexandra's Own Royal) Hussars20th Hussars21st (Empress of India's) LancersNorth Irish HorseSouth Irish HorseKing Edward's Horse (The King's Own Overseas Dominion Regiment)Royal Wiltshire Yeomanry (Prince of Wales's Own Royal Regiment)Warwickshire YeomanryYorkshire Hussars (Alexandra, Princess of Wales's Own)Nottinghamshire Yeomanry (Sherwood Rangers)Staffordshire Yeomanry (Queen's Own Royal Regiment)Shropshire YeomanryAyrshire (Earl of Carrick's Own) YeomanryCheshire Yeomanry (Earl of Chester's)Queen's Own Yorkshire DragoonsLeicestershire Yeomanry (Prince Albert's Own)North Somerset YeomanryDuke of Lancaster's Own YeomanryLanarkshire YeomanryNorthumberland HussarsNottinghamshire Yeomanry (South Nottinghamshire Hussars)Denbighshire HussarsWestmorland and Cumberland YeomanryPembroke Yeomanry (Castlemartin)Royal East Kent Yeomanry (The Duke of Connaught's Own)Hampshire YeomanryRoyal Buckinghamshire HussarsDerbyshire YeomanryQueen's Own Dorset YeomanryRoyal Gloucestershire HussarsHertfordshire YeomanryBerkshire Yeomanry1st County of London Yeomanry (Middlesex, Duke of Cambridge's Hussars)Royal 1st Devon YeomanrySuffolk Yeomanry (The Duke of York's Own Loyal Suffolk Hussars)Royal North Devon YeomanryQueen's Own Worcestershire HussarsQueen's Own West Kent YeomanryWest Somerset YeomanryQueen's Own Oxfordshire HussarsMontgomeryshire YeomanryLothians and Border HorseLanarkshire Yeomanry (Queen's Own Royal Glasgow and Lower Ward of Lanarkshire)Lancashire Hussars YeomanrySurrey Yeomanry (Queen Mary's Regiment)Fife and Forfar YeomanryNorfolk Yeomanry (The King's Own Royal Regiment)Sussex YeomanryGlamorganshire YeomanryWelsh Horse Yeomanry – formed in 1914Lincolnshire YeomanryCity of London Yeomanry (Rough Riders)2nd County of London Yeomanry (Westminster Dragoons)3rd County of London Yeomanry (Sharpshooters)Bedfordshire YeomanryEssex YeomanryNorthamptonshire YeomanryEast Riding of Yorkshire YeomanryLovat ScoutsScottish Horse – two regiments with a third formed in 1914Household Cavalry Composite RegimentReserve Cavalry RegimentsRoyal Regiment of Artillery consisting of three branches:Royal Horse ArtilleryRoyal Field ArtilleryRoyal Garrison ArtilleryCorps of Royal Engineers includingRoyal Engineers Signal ServiceGrenadier GuardsColdstream GuardsScots GuardsIrish GuardsWelsh Guards – formed in 1915Guards Machine Gun RegimentHousehold BattalionMost regiments had two regular battalions, supported by associated battalions from the Territorial Force ('part-time' soldiers) and Reserve Battalions. After the start of the war, many new battalions were raised and called "Service Battalions". Service battalions raised from a single locale were often called "Pals battalions".
Royal Scots (Lothian Regiment)Queen's (Royal West Surrey Regiment)Buffs (East Kent Regiment)King's Own (Royal Lancaster Regiment)Northumberland FusiliersRoyal Warwickshire RegimentRoyal Fusiliers (City of London Regiment)King's (Liverpool Regiment)Norfolk RegimentLincolnshire RegimentDevonshire RegimentSuffolk RegimentPrince Albert's (Somerset Light Infantry)Prince of Wales's Own (West Yorkshire Regiment)East Yorkshire RegimentBedfordshire RegimentLeicestershire RegimentRoyal Irish RegimentAlexandra, Princess of Wales's Own (Yorkshire Regiment)Lancashire FusiliersRoyal Scots FusiliersCheshire RegimentRoyal Welsh FusiliersSouth Wales BorderersKing's Own Scottish BorderersCameronians (Scottish Rifles)Royal Inniskilling FusiliersGloucestershire RegimentWorcestershire RegimentEast Lancashire RegimentEast Surrey RegimentDuke of Cornwall's Light InfantryDuke of Wellington's (West Riding Regiment)Border RegimentRoyal Sussex RegimentHampshire RegimentSouth Staffordshire RegimentDorsetshire RegimentPrince of Wales's Volunteers (South Lancashire Regiment)Welsh RegimentBlack Watch (Royal Highlanders)Oxfordshire and Buckinghamshire Light InfantryEssex RegimentSherwood Foresters (Nottinghamshire and Derbyshire Regiment)Loyal North Lancashire RegimentNorthamptonshire RegimentPrincess Charlotte of Wales's (Royal Berkshire Regiment)Queen's Own (Royal West Kent Regiment)King's Own (Yorkshire Light Infantry)King's (Shropshire Light Infantry)Duke of Cambridge's Own (Middlesex Regiment)King's Royal Rifle CorpsDuke of Edinburgh's (Wiltshire Regiment)Manchester RegimentPrince of Wales's (North Staffordshire Regiment)York and Lancaster RegimentDurham Light InfantryHighland Light InfantrySeaforth Highlanders (Ross-shire Buffs, The Duke of Albany's)Gordon HighlandersQueen's Own Cameron HighlandersRoyal Irish RiflesPrincess Victoria's (Royal Irish Fusiliers)Connaught RangersPrincess Louise's (Argyll and Sutherland Highlanders)Prince of Wales's Leinster Regiment (Royal Canadians)Royal Munster FusiliersRoyal Dublin FusiliersRifle Brigade (Prince Consort's Own)Infantry regiments of just Territorial Force battalions (i.e. no regular or Special Reserve battalions).
Honourable Artillery Company, T.F.Monmouthshire Regiment, T.F.Cambridgeshire Regiment, T.F.London Regiment, T.F.Inns of Court, T.F.Hertfordshire Regiment, T.F.Herefordshire Regiment, T.F.Northern Cyclist Battalion, T.F.Highland Cyclist Battalion, T.F.Kent Cyclist Battalion, T.F.Huntingdonshire Cyclist Battalion, T.F.Royal Militia of the Island of JerseyRoyal Guernsey Light InfantryMachine Gun CorpsMotor Machine Gun ServiceLabour CorpsArmy Service CorpsRoyal Army Medical CorpsArmy Veterinary CorpsTank CorpsArmy Ordnance CorpsArmy Cyclist CorpsRoyal Flying Corps (not separate at this time, but controlled by the War Office)Army Remount ServiceArmy Dental CorpsRoyal Army Pay CorpsArmy Chaplain Department