Flag of the United Kingdom
Native & traditional name: Union Flag / Union Jack
| Flag | United Kingdom (GB) |
|---|---|
| Type | National flag (national, civil, state, war) |
| Proportion | 1:2 (1:2) |
| Primary colors | blue, white, red |
| Main symbol | cross, saltire (×2) |
| Arrangement | centered saltire |
| Official adoption | 1801-01-01 — Royal Proclamation of King George III upon the Acts of Union 1800 uniting Great Britain and Ireland |
| Region | Northern Europe |
Plain-language visual description
The flag of the United Kingdom (the Union Jack) is a 1:2 royal-blue rectangular field combining three heraldic crosses: the centered red cross of St George bordered in white, the white diagonal saltire of St Andrew, and the counterchanged red diagonal saltire of St Patrick.
Construction and geometry
Proportion & symmetry: The Flag of the United Kingdom uses a statutory 1:2 height-to-width ratio on a rectangular field with none mirror symmetry. 30×60 unit grid (1:2). St George's red cross is 6 units wide with 2-unit white fimbriations; the red saltire arms (2 units) are counterchanged against St Andrew's white saltire so the wider 3-unit white border is on the top half at the hoist.
- Constructed on a 30×60 unit grid (1:2 ratio for land and maritime ensigns; the British Army uses a 3:5 war flag).
- St George's central red cross is 6 units wide (1/5 of height) with 2-unit white fimbriations; the diagonal saltire totals 6 units in width, split into a 3-unit white band, a 2-unit red band, and a 1-unit white fimbriation that alternates position across the four quarters.
Official colors and specification system
Rather than manufacturing false RGB precision where a statute specifies dyed cloth, Pantone, Munsell, or CIE coordinates, the table below records the governing color system alongside a calibrated display hex approximation.
| Color | Official shade name | Specification system | Statutory / standard code | Display hex |
|---|---|---|---|---|
| blue | Royal Blue | pantone | Pantone 280 C | #012169 |
| white | White | statute-named | Named in statute | #FFFFFF |
| red | Crimson Red | pantone | Pantone 186 C | #C8102E |
Meaning and symbolism
Documented symbolism
Established by Royal Proclamation on 1 January 1801, the Union Flag unites the patron-saint banners of three kingdoms: the red cross on white of St George ( representing England and Wales), the white saltire on blue of St Andrew (Scotland), and the red saltire on white of St Patrick (Ireland).
Common interpretations
Because the red diagonal arms of St Patrick's saltire are offset (counterchanged) within the white diagonal arms of St Andrew's saltire so thatNeither saltire relegates the other to a mere border, the flag is not upside-down symmetric: at the hoist side, the broader white diagonal stripe must always be above the red diagonal stripe.
History and design evolution
When King James VI of Scotland succeeded to the English throne as James I in 1603, he issued a Royal Proclamation on 12 April 1606 ordering ships of both nations to fly a combined flag superimposing the red Cross of St George (fimbriated in white) over the white Saltire of St Andrew on a blue field. After the 1707 Acts of Union, that two-cross banner became the flag of the Kingdom of Great Britain.
Following the Acts of Union 1800, which united Great Britain and the Kingdom of Ireland into the United Kingdom on 1 January 1801, the College of Arms added the red Saltire of St Patrick. To prevent St Andrew's white saltire from being reduced to a narrow border around St Patrick's red saltire, heralds counterchanged the two diagonal crosses in each quarter.
Through the British Red, Blue, and White Ensigns, the Union Flag became the canton of dozens of national, territorial, and state flags across the globe, including Australia, New Zealand, Fiji, Tuvalu, Bermuda, and the state of Hawaii.
Key historical milestones
- 1606First Union Flag of King James VI & I: Combines the Cross of St George and the Saltire of St Andrew for maritime use.
- 1707Acts of Union with Scotland: Adopted as the land and sea flag of the Kingdom of Great Britain.
- 1801Addition of St Patrick's Saltire: Royal Proclamation of 1 January 1801 introduces the counterchanged three-cross design.
Visually and structurally similar flags
Ranked deterministically across layout family (35%), color overlap and stripe order (25%), symbols (20%), aspect ratio (10%), and stripe/symmetry geometry (10%):
Sources and image-rights provenance
SVG artwork provenance: Constructed from statutory specifications (public-domain-statute, verified 2026-10-13, SHA-256 e0b1c3b6c198…).