In 1972, Idi Amin ordered the expulsion of Ugandan Asians from his blood-drenched, post-colonial kingdom. In culture, origins and appearance, they were clearly separate from Africans. They were also notably wealthier. Amin legitimised his rule by exploiting both race and class hatred, always a useful strategy for demagogues on the make. “I am going to ask Britain,” he boomed as he took back control, “to take over responsibility for all the Asians in Uganda because they are sabotaging the economy of the country.”

Suppose that in 2017 Britain even considered stripping the survivors of the 27,000 Asians who settled in Britain of their rights and leaving their children in limbo. As well as facing international accusations of racism and the targeting of minorities, the government would have to cope with uproar at home.

In 1973, the year after the Ugandan Asians arrived, Britain joined what became the European Union. EU nationals won the right to settle in Britain and vice versa. As the French singer and football writer, Philippe Auclair, says, the authorities don’t treat him and his fellow Europeans in Britain as members of an ethnic minority or series of ethnic minorities. Yet from nowhere they have been hit with the old combination of class hatred – you’ve made money at our expense – and race hatred – you’ve no right to be here.

But, but, I can hear respectable voices spluttering, there is no comparison. This is Britain, after all. We don’t have dictators with death squads at their command blaring out threats. The British character is moderate and tolerant, even if we say so ourselves, while the whole world acknowledges our famous sense of humour.

I don’t know about you, but I’ve found our willingness to do anything for a laugh has started to grate since the Brexit referendum. With the left banning speakers from universities and the right trying to police what academics think and say, our reputation for tolerance is not what it once was either.

As for moderation, Theresa May and Boris Johnson make cooing noises as they appear to offer firm commitments to EU citizens. So they should, as they must know it would wreck the economy if Europeans left in significant numbers. But they never find the guts to spell out Britain’s dependence to Tory England. Meanwhile, migrants and their children look in vain to find hard guarantees beyond the soft words. There can be no guarantees because all promises to EU migrants in Britain and vice versa will be meaningless if we crash out of the EU. As will all promises that jobs, living standards, peace in Ireland, trade and workplace and environmental standards will be protected.

A Brexit collapse would not only bring chaos but represent the worst abdication of political leadership in memory. Sooner or later, the public would realise that everyone with prominence in Westminster had been lying. Jeremy Corbyn and John McDonnell spent their careers opposing the EU on the infantile-leftist grounds that it was a capitalist club. Cunningly, they have kept middle-class support by pretending that their antipathy to Europe is less extreme than the antipathy on the Tory right. Readers tempted to believe the spin should remember Corbyn was so keen on yanking us out he advocated invoking article 50 the day after the referendum, an act of folly even Theresa May has not matched. Although she has come close.

May campaigned for Remain and even today cannot bring herself to say she would vote to leave the EU if the British had a second referendum. Her convictions notwithstanding, she still made herself the prisoner of the Tory right. A willing prisoner, I should add, a prisoner who locked herself up and threw away the key when she said we must leave the single market and customs union and, for good measure, made compromise impossible by adding that we should ignore European law. We should pause to reflect here the honesty that the direct democracy of a referendum was meant to bring to public life has resulted in an outbreak of lying without precedent in British political history.

There are deeper reasons for the breakdown of politics, which makes less comfortable reading. Labour MPs from northern England and Wales and Tory MPs who campaigned for Remain are not backing Leave now because they respect their leaders. Nor have they converted to the view that Brexit will enrich their constituents. They can see what liberals have missed: despite inflation and the fall in living standards, support for Brexit remains resilient. Until the polls move towards Remain with strides rather than baby steps, the politicians won’t move. And by the time they move, it may be too late.

In 1989, after the fall of the communist dictatorships in the Soviet empire and the fascistic dictatorships in Spain, Portugal and Greece, the German poet Hans Magnus Enzensberger wrote an essay entitled The Heroes of Retreat. The standard hero fights for a glorious cause, he said; they are men or women of unimpeachable integrity whose lives are celebrated. As essential are the far grubbier heroes of the retreat. No one will make a biopic on FW de Klerk’s slippery career in apartheid South Africa or the ambiguities in the lives of General Jaruzelski in communist Poland and Adolfo Suárez in Franco’s Spain. They had risen to the top by being complicit in state crimes. But when the moment of choice came they found the strength to tell their supporters that the game was up and their old slogans were now just meaningless noise. They called off the troops when they might have ordered them to fire and let their countries move forward.

“It was Clausewitz, that classic strategic thinker, who showed that retreat is the most difficult of all military operations,” concluded Enzensberger. Only horribly compromised politicians “who belonged to [the] innermost circle of power” were in a position to back away from dictatorship.

Where are Britain’s leaders who will tell 17.4m voters that the Brexit they were promised cannot be cashed? That the misery of migrants, the damage to the economy and our standing in the world will be for naught? Where are our prime minister and leader of the opposition? Where are their cabinet and shadow cabinet? We do not have men and women who can say, with regret, that whatever they once thought a hard Brexit is not working and was never going to work. It’s too much to hope for shining heroes who can lead us forward. But Britain doesn’t even have the heroes of the retreat.