The county of Middlesex dates from early Saxon times and its name refers to its origin as the territory of  the “Middle Saxons”. This region fell within the rule of the Kingdom of the East Saxons or Essex. With the advent of heraldry in the Middle Ages. heralds of the time also ascribed arms to ancient territories and lineages and the arrangement of three short notched swords was assigned to represent the ancient kingdom of Essex. The particular design of sword was termed the Seaxe and is thought to be the actual origin of the term Saxon, it being a weapon highly favoured by the warlike people. County authorities and military bodies from the two counties of Middlessex and Essex, that covered much of the territory of the ancient kingdom, all made use of these arms until in 1910 the Middlesex County Council applied to the College of Arms for a particular design to represent Middlesex alone and distinguish it from Essex. This was achieved with the addition of a Saxon crown, resulting in the The Middlesex Coat of Arms.

As with any coat of arms, the design on the shield could also be rendered in the form of a flag as a “banner of the arms” and this is effectively the flag of Middlesex; three gold hilted, white seaxes arranged horizontally, beneath a gold Saxon crown.

In 1889 a large portion of the traditional county of Middlesex was transferred to the newly formed authority of the London County Council forming much of modern north London. Then in 1965 the remaining part of the county was merged into Greater London ( with a few areas transferred to Hertfordshire and Surrey) and fell under the authority of the Greater London Council or GLC which in turn has been replaced by the GLA or Greater London Authority. The name is still in use officially however, as a Postal district – many of the districts in the far west and north of London have “Middlesex” addresses. Of course Middlesex County Cricket team still competes and enthusiasts keep the notion of the traditional county alive, under the concrete and traffic of the modern metropolis. The county arms can still be seen on a place name at the end of Kew Bridge, over the River Thames, by drivers coming from the south or Surrey side of the river.

Whilst banners of county arms are legally the property of the councils they represent and in theory are not meant to be used by individual citizens, the case with Middlesex is slightly different; on the one hand the basic design is so ancient that it predates any heraldic laws and so cannot be the sole property of any authority; additionally, even though the arms were amended by the addition of the Saxon crown, specifically for the Middlesex County Council, that body has ceased to exist so the flag is effectively up for grabs! Another issue with using county arms as flags is that they tend to be complicated heraldic patterns that do not make handsome flags but this is not really the case with Middlesex, where the pattern is fairly simple and rather bold.