LAST week, Palestinian schoolchildren joined a Queen Elizabeth II impersonator for a mock tea party set against the backdrop of Israel’s separation wall in Bethlehem. The festivities marked the latest installation by the graffiti artist Banksy. His artform, of course, is all about walls, and no wall in modern history has the psycho-political resonance of Israel’s 28-foot concrete boundary between the power of the global north and the tragedy of the global south.

This new work is Banksy’s simplest yet. It consists only of the words “er, sorry”.

Ultimately this is a high-concept dad joke: a pun. It refers to the acronym for Elizabeth Regina, the Queen’s cipher, and to the awkwardness we face as British citizens when confronted with the terrible deeds our state has committed in our name. The occasion for this is the centenary of the Balfour Declaration, where the British Empire promised Palestinian land to the movement that would form Israel, marking the beginning of the Middle East as a modern political disaster.

Balfour’s letter was never about sympathy for the Jewish people. Indeed, the British ruling class of the time was chock-full of posh anti-Semitism. The real intention was to undermine the French, to secure the Suez Canal and to create “a loyal Jewish Ulster” that would do Britain’s bidding, in the words of Ronald Storrs, the British military governor of Jerusalem.

Such low motives, to divide and rule and secure advantages over rival powers, were the hallmark of our diplomacy. The Palestinian Nakba is just one indicative instance of the disasters this has left across the world. After all, Israel’s “separation barrier” isn’t the only monstrous military wall erected in honour of British foreign policy. You’ll find similar monuments to barbarism in Cyprus, Ireland and Kashmir, to name only a few. All of them, in their way, are every bit as ghastly as the more infamous Berlin Wall. As people who aspire to be civilised, what more can we say, except “er, sorry”?

Unfortunately, you won’t hear these words from any UK politician. Instead, British reactions to the Balfour centenary range from remorselessly colonialist (Boris Johnson) to pitifully squeamish (Emily Thornberry). Johnson is hardly worth considering, since his approach to diplomacy is nothing but Tory-toff Trump. I shall give his article no further mention: I’ve already given it more than it deserves.

Thornberry’s seemingly more nuanced words are, in any case, just as depressing for any British citizen who is familiar with the history of the Middle East. In fairness, Thornberry argues that there should be a Palestinian state. She has even uttered one or two criticisms of Israeli policy. However, her negative comments have been exclusively directed at Israeli prime minister Benjamin Netanyahu’s recent actions, as if the current Israeli administration is an exception to the Israeli norm. You’ll find far more searching criticisms of Netanyahu’s policies – and, indeed, of Israel’s historical record before then – in impeccably Zionist Israeli newspapers like Haaretz.

Aside from these quibbles, Thornberry’s speech was an all-out defence of Britain’s tradition of uncritically supporting the Israeli state. It never addresses the illegal military occupation and settlements; the jailing without trial of thousands of Palestinians in the Occupied Territories; the colonisation of Palestinian resources; the millions of refugees living abroad; or the vast numbers of unarmed Palestinian casualties at the hands of Israel’s ultra high-tech armed forces. Instead it speaks of “modern Israel … as a beacon of freedom, equality and democracy … despite challenges that we must address in respect of relations with the Palestinian people”, a sentence which should be taught in English classes as a textbook example of the art of euphemism.

It gets worse. Supporting the creation of Israel becomes a “socialist, internationalist” cause. No mention of the 800,000 Palestinians violently displaced by the creation of Israel, which formed the basis of what remains, today, the largest community of displaced people in the world.

I’m not worried about the philosophical question of “Zionism” here. I’ll leave America’s fundamentalist Christians to debate that one. Instead, I’m looking on this as an exemplary case of how British politicians address our brutally violent history. Thornberry, like so many before her, seems utterly indifferent to the appalling suffering we’ve inflicted on the world. Our politicians who created this mess, and continue to justify it, are arguably far worse than the Israeli nationalists who are merely asserting their own claims, greedily, but understandably. After all, all-powerful British and American policymakers have actively encouraged and lavishly funded Israel to be as nationalist as possible – so who is really to blame?

In Thornberry’s speech, a future Palestinian state becomes “the completion of Balfour’s mission”. Sadly, that’s probably true, in the darkest possible sense. Israel’s illegal barriers and settlements have so thoroughly ripped the West Bank to bits that any state arising from the Occupied Territories will be “Balfourised” – that is, a dependent plaything of imperial powers, weakened beyond recognition, incapable of asserting any meaningful sovereignty or democracy. The state of Gaza, of course, is far worse.

If Britain had any self-respect, Banksy’s tea party in Bethlehem would be a real event. The actual Queen Elizabeth, plus Thornberry and Johnson, would spend the night at Bethlehem’s Walled Off Hotel, which proudly boasts a fine collection of art and the world’s worst view, since all its rooms look out on to a 28-feet high colonial wall.

Then Britain’s dignitaries, in all their finery, would step out and visit Bethlehem’s Aida refugee camp, home to the descendants of those who fled from Israeli reprisals in Jerusalem and Hebron. They’d meet a cramped population of several thousand human beings who have two schools and no health centres or pharmacies. And they’d say, “sorry”. Oh dear – we are so sorry. We don’t know why we do these terrible things. We don’t know; but we’re sorry. And they’d beg for forgiveness.