UPDATE - two useful comments
I am confused: if we are to be better disposed to the Turks in Britain for their help in defeating the Armada, are we to be less well disposed to Spaniards for sending it? If history is to help social cohesion, is that because we look generally to our history as the root of identity, or pull out only those parts convenient to a multi-cultural narrative?
It is an approach to history that says we should be close to the peoples of the Indian sub-continent because 2.5m volunteered in the 2nd World War, but suppresses the fact that 40% of Indian Army prisoners taken by the Japanese at Singapore switched sides. Which means that, whatever praise we rightly give to those who volunteered, how far their actions reflect on India/Pakistan/Bangladesh as a whole, is more complicated.
The truth is that history is a very big picture. The role of the Ottomans in the Armada may have been important, but then there were plenty of other very important factors. A historian may run an argument bringing such factors to the surface (eg: AJP Taylor used to draw out factors like railway timetables as a reason for WWI starting), but it isn't really acceptable where there is a fairly avowed political motive. It is essentially what left wing historians have always despised: nation building history.
What annoys those who this article attacks is the constant attempt to hunt the ethnic minority angle in every part of British history. Given the usual dismissal of history as a major source of national identity, this is rather opportunistic. It ignores that in many important parts of British history there is no meaningful (or even meaningless) minority angle, eg: Wars of the Roses. It also assumes that black and Asian Britons can't look at events involving only white Britons and see their countrymen. It means that we end up editing important parts of British history because they don't provide support to the multi-cultural reading.
I know the post-modernists amongst you think that all history is made up, so what is wrong with making up a new history? But history is, as Ranke said, about trying to tell it how it really was. Promoting minor events into earth-shattering importance is an amusing counter-factual game, but ultimately such minor events sink back into the background.
The progressives must face it: multi-ethnic Britain's origins owe almost everything to post-War immigration. The small and sporadic presence of black and Asian people during previous centuries is of incidental importance. Without post-War immigration, the B.E.M. communities would still amount to less than 1% of the population. Without the pre-Windrush presence, the B.E.M. communities would be about the same size as they are today. The presence of absence of a few more historic forebears neither adds to nor diminishes the rights of the ethnic minority communities. However, building their rights on bad history can only be harmful.
And fernickity :
I'm surprised so few commentators are interested in whether it's actually true that the Turks gave the aid that Jerry Brotton proposes they did. In fact, this question was looked at in great detail by Edwin Pears in the 1890s, with the results published in his article "The Spanish Armada and the Ottoman Porte", published in the English Historical Review, vol. 8 (1893), pp. 439-66. He went over the extensive correspondence between Walsingham and the English ambassadors to the Ottomans, William Harborne and his successor Edward Barton, in great detail (the letter Brotton mentions is just one among many), and although they had been urging the Turks to make a joint attack on Spain from the early 1580s (on the grounds that Protestants, like Muslims, were anti-idolaters and thus had a common interest in defeating Catholic Spain), and Sultan Murad III had promised to make such joint action, the letters show that no naval action was ever actually performed: the Turks were simply too busy with internal revolt and war on their eastern front, and the governor of Constantinople, one of Murad's principal advisers, was being bribed 60,000 ducats a year by the Spanish precisely to prevent their intervention. As Pears states: "The defeat of Lepanto, the war with Persia, and the rising of the subject provinces in North Africa did much to deter the Turk from lending aid. The heavy bribes by which Spain was able to obtain the support of the ministers and favourites of the sultan probably did more." So contrary to Dave Hill's remark, opinion is not divided about whether the Turks intervened or not: there is simply no evidence that they did, and quite a lot of evidence that they didn't. Is Jerry Brotton simply unaware of this earlier research, which I've discovered simply by googling? It sounds like it.
Ferickity is obviously an academic, because the documents he quotes are subscription-only via JSTOR, to which most university libraries subscribe. But it seems that he's banged the final nail into the rotten Brotton theory's coffin.