As I write, highly educated if wholly uncivilised human beings are travelling underground, trying to kill me. But their aim is to murder more than just me, or you. Despite the appeasing rationalisations of John Pilger - that it wouldn't happen if only we cut and run from Iraq, or if we stopped supporting Israel - these terrorists are engaged in an assault on our way of life. As the Prime Minister has rightly suggested, British values are the true target of the terrorists. So, what exactly are we fighting for?
It was, of course, George Orwell who famously pointed out the prevarications of British intellectuals over patriotism. In his essays he ridiculed their embarrassed avoidance of nationalism while he revelled in England's invincible suburbs, its old maids, its pillar boxes and pigeon-fanciers. Fifty years on, the left's hesitations about national identity remain, not least because left-wingers have an instinctive reluctance towards aligning themselves with the Great Britain camp. For few right-thinking people today are comfortable with the sub-G K Chesterton guff of Simon Heffer or Peter Hitchens: that staid conception of a Britain rooted in mirages of nuclear families, hallowed authority, stultifying tradition and the cultural flotsam of empire. In effect, we have been put off patriotism by the conservative codification of it. Yet with Islamo-fascism claiming lives in London, Madrid, Amsterdam and elsewhere, it is increasingly unsustainable to maintain this refusal to engage with the virtues of nationhood.
Part of the problem for the left has been the curious nature of the British state. We are a monarchy not a republic, so while French and American liberals are happy to sign up to Liberty, Equality and Fraternity and celebrate the ideals of the founding fathers, British progressives have been slightly less enthusiastic about swearing fealty to the heirs and successors of the House of Windsor. But there is another story of Britishness beyond the conservative trinity of royalty, church and army which we need desperately to defend from the bastardised theology of the terrorists.
Gordon Brown has long argued that Britishness is about values rather than institutions, and he is right, up to a point. Those values, moreover, are intrinsically hateful to the medieval mindset of al-Qaeda. Like other western and non-western nations, we have a history of promoting the type of gender, racial and sexual equality reviled by misogynistic mujahids. From the Married Women's Property Act 1882 to the Race Relations Act 1976, Britain has progressively advanced the cause of personal equality - something apparently forgotten by Ken Livingstone, who happily promotes Gay Pride marches, but at the same time invites sexist, homophobic (and inevitably anti-Semitic) clerics to lecture London on interfaith harmony.
Britain can also boast a superb record of political liberalism and intellectual inquiry, giving us a public sphere open to ideas, religions and philosophy from across the world. Again, this is something which infuriates the fundamentalist mindset and which British authorities have been far too willing to compromise. When the history of Islamic terrorism in this country is written, the dreadful failure of nerve by the political establishment during the Rushdie affair will surely feature pro-minently. How did Britain - home to the iconoclasm of Milton, Marx and the Sex Pistols - allow book-burning and fatwas to be decreed openly, in the streets of south Yorkshire?
(Here, a brief diversion. It is often suggested that a central component of Britain's history is its openness to radicals and insurgents. Turning the capital into "Londonistan" during the 1990s was, we are assured, no different from Victorian London welcoming in Marx and Engels. But the critical difference was that both of those men adored England. Engels loved English poetry - entertaining guests with his rendition of "The Vicar of Bray" - and chose the coast near Eastbourne as his final resting place. Marx was never happier than in sleazy Soho dens, walking on Hampstead Heath or retreating to the British Library.)
One could go on with a stirring list of progressive British attributes: political pluralism, rationalism and radicalism, nonconformity and anti-clericalism, representative democracy, technological inventiveness, entrepreneurialism, religious tolerance (seen to such effect in differing attitudes to the hijab in France and Britain) and moral internationalism, from the anti-slavery movement to Make Poverty History.
With all this has developed an amorphous but nevertheless peculiarly British culture at whose root is a healthy irreverence towards religious and political authority. We like burning effigies of the Pope, wearing masks of Tony Blair, exposing the peccadillos of pious statesmen. What Islamic ideologues dismiss as western decadence, I like to think of as bawdiness: our high propensity for drunkenness, historic prevalence of illegitimacy, and astoundingly revealing clothing. More productive is our tradition of civil society and civic duty, to which postwar Muslim communities have contributed so markedly. We share with America a vibrant culture of clubs, institutes and volunteering, from the Manchester Unity of Oddfellows to the Manchester United supporters' club. Much of it is indeed built around sport - and what greater contrast could there be than that between the effusive patriotism of the boxing prodigy Amir Khan and the narcissistic suicide of the cricket-loving terrorist Mohammad Sidique Khan?
While progressives can value all this, our Achilles heel is our belief in progress: our conviction that all is not for the best in the best possible nation, that there are faults and inequalities in past and present Britain. It is this more cerebral engagement with the realities of nationhood that opens the left to the calumny that it lacks patriotism. Dissent, protest and reform are themselves very much part of the British story, however.
Unfortunately, our otherwise progressive government has not always acted to protect these cultural traditions. The French newspaper Le Figaro rightly remarked on the irony of MPs outlawing fox-hunting - a historic component of British culture in art, literature and the very contours of our natural heritage - while happily allowing in Muslim clerics committed to destroying British values. At the same time, institutional political correctness in local government allowed notions of a sacrosanct multiculturalism to be placed above the rule of law in the tragic case of Victoria Climbie.
By bending over backwards to accommodate the cultures and religions of migrant communities, we have been in danger of undermining the very ideals that attracted immigrants here to begin with. One of the few politicians brave enough to confront this dilemma has been David Blunkett. The teaching of citizenship in schools, the introduction of citizenship ceremonies, and the publication by Bernard Crick of an official history of Britain have served to return the emphasis to British values. Meanwhile, Blunkett himself has happily broken with the left's usual reserve on these matters, speaking of his patriotic ardour for English music, poetry, drama and humour.
The terrible events of 7 July should strengthen our debate about the nature of Britain. In America, the neoconservatives ruthlessly exploited the 11 September 2001 attacks to pursue long-held foreign-policy objectives. We must respond differently, by looking in on ourselves and unpicking the values and customs that brought this incredibly cosmopolitan collection of individuals to our capital city. We must then relearn and reassert for future generations precisely those elements of British identity which the bombers and bigots find so appalling. That is what we are fighting for.
What makes this place great?
Dylan Jones Editor, GQ
Gentrification, law and order, freedom, Christianity (of one sort or another), an economic safety net, an expanding middle class, Civilisation with a big hand-carved C, the BBC, the Beatles, Wiltshire, minicab offices, Tesco, Wogan, topiary, very good national newspapers, Routemaster buses (RIP), Robbie Williams . . .
David Hare Playwright
Freedom of speech - as currently threatened by the thought crime bill and the bill against incitement to religious hatred.
Ruth Kelly Education Secretary
We have cultivated collective solidarity while protecting people's right to private beliefs. This tolerance must be defended, but the bombings force difficult questions on us. How can we accentuate the shared modern British experience while maintaining our traditional tolerance?
Lynne Truss Author
There's something fantastically British about our broadcasting, radio in particular, that means I could never live abroad. Despite the speed of broadband internet, it just isn't the same.
Holly Johnson Artist/musician
Not the press, that's for sure. Why not ask the asylum-seekers, economic refugees and, most importantly, the droves of British people who are buying property abroad?
Robert McCrum Author
First, the English language, and second, the location, by which I mean being an island. These have had a huge role in determining our "greatness".
Oona King Politician
British multiculturalism has been successful because it promotes integration rather than assimilation, but segregation still has a toehold. To build on the most evocative notion of Britishness - quintessentially, fair play - we need to knit our communities together.
Roy Hattersley Politician/writer
I like the landscape, the literature, the language and even the weather, but I do not pretend we are braver than the French, more moderate than the Germans or more cultivated than the Spanish.
Sadiq Khan MP Politician
Openness, fair play, equality. London is the most diverse city in the world and the secret of its success is that we're very much at ease with ourselves.
Billy Bragg Musician
The diversity of the people and the diversity of the heritage. That isn't just about modern multiculturalism, it's about how historically people have come together from four different nations as well.
Joan Bakewell Broadcaster
Tolerance, understanding, humanity and self-esteem - but in those we're no greater than anyone else is.