This morning, a fierce debate erupted over the accuracy of a statement from a ‘No. 10 source’ that claimed to describe a telephone conversation between Boris Johnson and Angela Merkel. According to this leak, the German Chancellor “made clear a deal is overwhelmingly unlikely and she thinks the EU has a veto on us leaving the Customs Union”.

The source alleged, “Merkel said that if Germany wanted to leave the EU they could do it no problem but the UK cannot leave without leaving Northern Ireland behind in a customs union and in full alignment (with the single market) forever.”

People with experience of dealing with the German Chancellor said this description didn’t reflect the style and tone she uses during official exchanges. The Times’ Brussels correspondent, Bruno Waterfield, tweeted, “veteran diplomats and Brexit negotiators . . . don’t recognise the Downing Street account of the Merkel call.”

Donald Tusk accused Boris Johnson of instigating a ‘blame game’, ahead of an expected collapse in negotiations. Officials in Brussels think Britain will walk away from talks later this week and they see this as a pre-emptive attempt to insinuate that EU intransigence is the cause.

The row misses an important point.

It matters very little whether the No. 10 statement was an accurate account of Angela Merkel’s language and tone. It matters much more whether it conveyed the meaning of the German Chancellor’s message – and there’s no reason to doubt that it did.

The supposed content of the telephone call echoes official statements from the EU and the Dublin government. Unless Brussels’ position has changed, then it is an entirely accurate interpretation of the backstop, its purpose and its likely effects.

The proposals Boris Johnson made to the EU last week were an extraordinary offer to drive an economic and political border down the middle of the UK. They placed Northern Ireland, at least for the time being, under the rules of the single market, without giving it a voice in Brussels. And to endow this plan with a vestige of accountability, they made a hazy commitment to seek the province’s consent.

But even this extraordinary land grab is not enough for the EU and its attack dogs in Dublin. They will settle for nothing less than the full annexation of an integral part of Britain’s territory so that it has no way back to the British internal market or the UK’s political, social and economic life. Northern Ireland must be surrendered completely to the EU, and it must be forever.

This strategy has scarcely changed since officials in Brussels and Irish nationalists started calling for ‘special status’ for the province, shortly after the referendum result.

They can never have expected, though, to get this close to their goal or have it so widely accepted.

Theresa May’s government conceded the principle that there must be no new infrastructure, no matter how inconspicuous, to check goods moving between Northern Ireland and the Republic. Throughout the negotiations, nationalists’ anxieties about a potential hardening of the Irish border have been given priority over unionists’ worries that their place in the UK will be compromised.

The propaganda in favour of a backstop has been unrelenting and perhaps the best illustration of the effects of this onslaught is the reaction of Northern Ireland’s business community. The province buys six times more goods from Great Britain than it buys from the Republic. It sells four times more to the mainland than it sells south of the Irish frontier. Yet, business organisations have devoted their attention almost exclusively to cross border trade.

Meanwhile, even a regulatory border in the Irish Sea threatens to affect how nationwide retailers stock their outlets in Ulster, compromise supply chains from GB to NI and dissuade small companies and internet firms from selling to the province altogether. Nearly one year after the backstop was set out in detail in the draft Withdrawal Agreement, I’m aware of only one, relatively obscure report that attempted to measure its likely impact on Northern Ireland’s economy and, even then, it was a side note to the main content.

Under May, the government had little incentive to contradict the EU and the Irish government. According to her chief negotiator, the prime minister viewed the backstop as a ‘bridge’ to a new, permanent customs relationship between the UK and Brussels. It was an excuse to keep Britain aligned closely with the EU.

By the time Boris Johnson became prime minister, it was almost too late to counter three years of sanctimonious preaching about the necessity of a border in the Irish Sea. Last week he undermined his argument that the EU has no right to drive a wedge between two parts of the UK, by accepting that Northern Ireland should stay in the single market.

Unionists in Northern Ireland have been let down badly by their government and the DUP. But they will recognise in the leaked account of Merkel’s comments only a bald, truthful description of the EU’s backstop policy.