Quick answer
The Blue Ensign has a blue field with the Union Flag in the upper hoist canton. The plain, or undefaced, form has no additional badge; authorised defaced forms carry identifying devices. It remains in maritime use under specific authorisations. Royal Navy regulations distinguish plain and defaced forms.
| Feature | Description | Evidence status |
|---|---|---|
| Plain design | Blue field with the Union Flag in the canton; no additional badge. | Identifying arrangement; see The Colours of the Fleet. |
| Overall proportions | 1:2, measured hoist to fly. | Customary manufacture reported by the Flag Institute; not presented here as a universal statutory requirement. |
| Defaced variants | Authorised versions have distinctive badges or seals. | Royal Navy regulations distinguish these from the plain ensign; each variant needs its own evidence. |
| Physical colours | Blue field; red, white and blue in the Union canton. | No Blue Ensign-specific textile colour standard was verified for this record. |
| Detailed geometry | Exact canton dimensions, stripe widths and production tolerances are not specified here. | No dimensioned official manufacturing drawing was verified. |
Construction and reproduction
The Flag Institute’s protocol guide describes 1:2 as customary for ensigns. On that basis, a reference rectangle has twice as much fly as hoist. This does not establish the dimensions of every historical specimen.
Preserve the Union Flag’s asymmetrical diagonals: in the half nearest the hoist, the broader white diagonal lies above the red diagonal. See the separate Union Flag record.
Official authorisation to use an ensign and a manufacturing specification are different evidence. No exact Pantone, textile, RGB or hexadecimal values are asserted here. Screen colours would be approximations unless supported by an applicable digital specification; an editorial reconstruction would need to identify its construction source and limitations.
Authorised maritime use
BRd 2, article 9153, lists plain-ensign users including specified Royal Research Ships, merchant vessels whose masters hold the required warrant, and qualifying yachts. Defaced versions identify authorised organisations and clubs. Entitlement depends on the applicable conditions, not simply British registration. Consult article 9153 for the detailed categories and requirements.
Historical development
The current Union Flag dates from 1801. Royal Museums Greenwich identifies its Blue Ensign specimen AAA0746 as a post-1801 design and dates it to circa 1807. That qualified date describes the object, not a precisely established adoption date for every Blue Ensign.
The Royal Navy’s regulations identify 1864 as the end of the squadronal system and the reservation of the Blue Ensign for government-service vessels. This was a change of allocation, not the first appearance of a blue naval ensign.
Specimen AAA0746 is hand-sewn silk, with linen reinforcement and a hoisting rope. Its recorded dimensions are 1066.8 × 1371.6 mm, illustrating why the modern customary 1:2 proportion should not be imposed on every surviving historical flag.
Related records
Compare the Red Ensign, White Ensign and Union Flag.
Sources
- Royal Navy, BRd 2, October 2025 version, article 9153: official usage categories and the 1864 allocation.
- Flag Institute, UK flag protocol: customary ensign proportions and Union Flag orientation.
- Royal Museums Greenwich, AAA0746: historical specimen, qualified date, materials and measurements.
- Malcolm Farrow, The Colours of the Fleet, edited by David Prothero, December 2011: ensign design reference.