Jingoism is a particularly British strain of belligerent nationalism. It comes decked not only in the union flag, but with a long trail of imperial relics meant to signify that we are still a world power. You could hear it in David Cameron's speech in Edinburgh on Thursday, when he invoked Britain's seat on the UN security council and prominent position in Nato. It's there when his back-benchers liken the European Union to the Third Reich. And we saw it last week in images of the gunboat that we have hastily dispatched to defend the Falklands.

Now that Cameron appears to have ruled out the status quo by promising greater devolution to the Scots if they vote no to independence, we're likely to hear more about how great Britain is in the days to come. For jingo is the default reaction of the English ruling class when they feel their interests are under threat. Unsure about our true position in a changing world, they hold on to the union flag like a comfort blanket, wrapping themselves in it to enhance their sense of importance.

While the Scots seem confident about their future, a Little Englander mentality is in danger of taking hold south of the border, in which every external challenge is perceived as a threat. This attitude can already be detected in the search for a new manager for our national football team. The media are calling for an Englishman, but shouldn't we be demanding the best man for the job, wherever he's from?

Our overblown sporting expectations are a hangover from an imperial past in which we not only ruled the world, but also taught everyone how to play soccer, rugger, cricket and tennis. We English have never been able to shake off the feeling that, having invented all these games, we should be the world champions, hence our continual disappointment with our miserable performances in Test matches, World Cups and Wimbledon.

More dangerously, our imperial instincts remain so strong that we are often to be found in the front rank of any military intervention, willing to deploy our troops into situations where even the genuine superpowers are reluctant to tread. "By Jingo" was the refrain of a music-hall song that was taken up as the rallying cry for those spoiling for war with Russia in 1878. That same aggressive clamour could be heard in the spurious justifications for the overthrow of Saddam Hussein.

If the ultimate outcome of the Greek crisis is a greater integration among eurozone members, then Britain will find itself isolated in Europe while at the same time debating whether or not it wishes to remain a united kingdom. The English will be caught in a double bind, with the future of Britain being decided in Edinburgh, while the future of Europe is debated in Brussels.

The rattling of the old jingoistic sword is a sure sign that the English ruling class feels its power ebbing away, torn between a European super-state, the aspirations of the Celtic fringe and demographic changes within England itself. Whether the English can awake from their long dream of empire and use this opportunity to renew their sense of identity remains to be seen.

Unless and until we throw off our imperial pretensions and begin to relate to our neighbours as equals, joining with them in creating new networks of active devolution and shared sovereignty, we English are in danger of becoming an insular people, jealously guarding the right to make our own laws while increasingly unable to control our destiny.

• Follow Comment is free on Twitter @commentisfree