The first Union Jack was made up in 1606, three years after the accession of James VI of Scotland as James I of England. James wanted to be king of a union state called "Great Britain", but he underestimated English recalcitrance. To press his claim, he made do instead with cross border economic policies and doses of Union-British symbolism. A British flag was part of this and, though it was originally intended to be flown from the main top masts of ships, smaller versions started fluttering from upright spars on the bowsprit. These were called "jackstaffs".
James's flag designers had to observe heraldic conventions and the unity, and the independence, of the two kingdoms. In the end, they settled for patron saints' crosses imposed one on top of the other. Who got on top was solved by laying St George's red cross over St Andrew's silver saltire for English ships, and Andrew's silver over George's red for Scottish ships. As there were far fewer Scottish ships than English, the silver version wasn't much regarded, though it lasted into Victorian times.
During the British and Irish civil wars, the Jack took a buffeting. Against the Royal Standard, the English revolutionaries raised the red cross of St George (as the Peasants' Revolt had done in 1381). In 1649 Parliament declared it the English national flag. The Scots, meanwhile, returned to the flag in Cromwell's Commonwealth union of 1654 - which quartered cross and saltire with an Irish harp in one corner and the Protector's white lion at the centre.
The Jack came back with the restoration of the Stuarts in 1660, and apart from some fiddling with the white edges, stayed more or less intact up to Anglo Scottish Union in 1707. During the 18th century it established itself alongside Britannia and John Bull as a potent symbol of British imperialism. Navy blues came to predominate over paler blues: a darker field was better able to withstand wind and rain.
Union with Ireland in 1800 presented the designers with a saint without a cross. In his time, St Patrick had overcome many problems, but how was he to engineer his martyrdom 1300 years after his death? The heraldic answer lay in the ancient royal house of FitzGerald whose red saltire had stood for Ireland before, and now would do so again. This is the flag we know: a red Irish saltire, narrowed and lowered, over a white Scottish saltire on a navy blue field, with the red cross of England laid squarely over them both. The Welsh, who have been in the Union from the start, have never been in the flag; and the Irish, who were last in and first out, so to speak, are in the flag still.
In fact, Groom is at his best before 1606, when he leaves most of the political history to others, and expounds on the origin of emblems. Roman eagles were met by heavily tattooed "Britons" - a word stemming from the Celtic "pritani", or "people of the design". With the church appeared the vexillum - a reliquary draped in cloth that often accompanied warrior saints into battle. At Hastings, Harold went down fighting bearing the Golden Dragon of Wessex. After 1066, English dragons were out, French lions were in: one for Aelis of Louvain, two for William of Normandy, three for Eleanor of Aquitaine, and four for Geoffrey of Anjou.
In the early chapters, Groom's clarity of purpose serves us well. The nearer he gets to a New Labour present, however, the more his history flattens into a tedious narrative of what came next from the newspapers. I went to bed thinking not of new Union Jackery, but of chained Danish ravens, howling Saxon dragons and Harald Hardrada's black banner, Landeydan, or "Land-Waster".
Robert Colls is Professor of English History at the University of LeicesterReuse content