10 January 2013 Last updated at 09:30 ET

The union jack: A very complex flag

By Richard Cable BBC Knowledge & Learning

Flags are powerful symbols of identity and belonging, and few are as instantly recognisable as the union flag.

Whether draped around Olympic athletes or the focus of protests in Northern Ireland, this quintessential emblem of Britishness has been the focus of controversy and high emotion since it was first flown more than 400 years ago.

It made its earliest appearance in 1606. James VI of Scotland had recently ascended to the throne of England, bringing the two countries together in a new realm he styled "the Kingdom of Great Britain".

His ships were commanded to fly a flag that combined the red cross of Saint George and the white cross (saltire) of Saint Andrew.

Unhappy unions

Predictably, some Scots were unhappy that English Saint George overlaid Scottish Saint Andrew and a design for a "Scottish union flag" was put forward, placing the white cross over the red. The issue was settled in 1707 by Queen Anne, who chose red over white from a variety of designs.

That same year, the Acts of Union were passed, unifying the two crowns and the two parliaments in one united kingdom.

A further Act of Union, this time with Ireland in 1801, gave us the union flag we recognise today, when the red cross of Saint Patrick was added.

If the union itself proved to be contentious, so did the flag chosen to represent it.

Debate continues even now over the provenance of Saint Patrick's flag, with claims it is a British invention or simply "lifted" from the arms of an aristocratic Irish family.

Nonetheless, the union flag survived the partition of Ireland in 1921 and the Saint Patrick element of it continues to represent the place of Northern Ireland within the United Kingdom.

It is for this reason the decision to restrict the flying of the union flag over Belfast's City Hall is seen by many in the unionist and loyalist communities as an attack on their cultural identity, leading to large scale public protests and, for a small minority, violent confrontations and rioting.

What about Wales?

Then there is the one glaring omission: Wales. Because Wales was annexed by England's Edward I back in 1282 and then "integrated" during the 16th Century, its place in the flag is represented by the cross of Saint George.

In 2007, MP Ian Lucas campaigned for the inclusion of the Welsh dragon in the union flag. But while it was conceded he had raised a valid point, no changes were made.

Uniquely, the union flag has been - and for many still is - a feature of the flags of several other nations, a legacy of the size and endurance of the British empire. Many, such as Canada, South Africa and Hong Kong, have since dispensed with the emblem of their former colonial rulers.

Others, such as New Zealand and Australia, have chosen to retain the symbols of their close connection with Britain by keeping the union flag in the canton (upper left hand corner) of their national flags. Fiji retains it despite independence and having left the Commonwealth.

Flag versus jack

Even the original flag of the United States, first raised in 1775 was "a jack with the union flag, and striped red and white in the field". Notably, Hawaii retains the union flag in the canton of its flag - the only state to do so.

Given its prominence, reach and power, it is strange to note that the union flag has no official status in British law and is only regarded as the national flag by virtue of "custom and practice".

The closest it comes to formal recognition is a reply to a parliamentary question in 1908, when the Earl of Crewe stated: "The union jack should be regarded as the national flag". (A private member's bill in 2008 aimed at rectifying this oddity failed to get a second reading.)

And before suggesting the Earl of Crewe didn't know his jack from his flag, it seems that both terms are equally acceptable.

According to the Flag Institute, a leading research centre that manages the United Kingdom Flag Registry, it is a "relatively recent idea" that the flag is only a jack when flown from a warship.

Uncertain future

The union flag has a history that is as convoluted, complex and emotive as that of the nations it represents.

Even so, it seems to possess an unerring ability to work its way into the indelible images of the centuries, from Waterloo to the Who, from Victory in Europe to Cool Britannia, from tragedy of Scott of the Antarctic to the triumphs of Team GB.

For others it retains dark echoes of our colonial past or the taint of a period when it was co-opted as the emblem of the racist far right. It is heartening that in the UK at least, the union flag is these days more closely associated with bunting than boot-boys.

But despite its global status at the emblem of "brand UK", the future of the union flag is by no means assured. Should Scotland vote for independence in 2014, the flag created to recognise the union with England could well be one of the first casualties.

For now, the heraldry authorities are saying they will cross that bridge when they come to it.