Can Ireland sink Brexit? It does not augur well that, ever since the 1998 Good Friday agreement, the London political class has lost all interest or knowledge in Irish politics.

As a result, London has lost touch with the deep currents of Irish politics. Few UK papers have correspondents in Dublin or columnists who know the current politics of the island.

The one exception curiously is the current Labour leadership. Jeremy Corbyn has long been interested in Ireland. At the time, he was much criticized by the tabloid press because he held talks with Sinn Fein leaders as long ago as 1984 who were elected as British MPs even if they never took their seats.

John McDonnell, Corbyn’s No 2, with his Irish background is also more aware of the Irish dimension of Brexit. He understands Irish politics better than most Tory ministers.

“News” in British newspapers

In British newspapers, the news that the Irish government in Dublin needs assurances is seen as a shocking last-minute development.

Irish leaders want assurances in writing, signed by the UK Prime Minister, that the Peace Deal in Northern Ireland must not be jeopardized by re-introducing customs controls on the border between the six counties of Ulster under British control.

That this should be considered news at all is all the more astonishing as Michel Barnier has been making this clear all year. He has stated numerous times that, if the UK leaves the Customs Union, there would have to be customs posts on the Northern Ireland border.

Barnier told me back in spring when I was researching a new book on Brexit that he had told the French government they had to create customs clearing posts on all French ports that can take in vessels from the UK assuming the UK leaves the Customs Union.

The idea that the EU27 would allow free passage of meat, milk, whiskey and manufactured goods not made under enforceable EU norms and regulations, including rules of origin, goes against all legal norms governing trade between countries that belong to two different sets of customs rules.

The UK as a “Third Country”

After all, with Brexit, the UK becomes a so-called “Third Country.” Trade then flows between the EU and the (non-EU) UK.

The high hopes that the Tories maintain about finding a “bespoke” form of a different deal is impossible to envisage.

All it needs is, for example, an outbreak of some animal disease. The health-conscious Germans, as well as other Northern European nations would never allow free passage of animals or meat any longer because it is not covered by enforceable EU rules. The French also would not go along for sure.

There are 2.4 million vehicle crossings every month through about 200 roads (most tiny) between the UK’s Northern Ireland and the EU’s Ireland. The idea there should not be any custom controls between two completely different trade blocks is a smuggler’s idea of paradise.

The history of Fine Gael — the minority party in the Dail, the country’s national parliament, that forms the national government – also needs to be considered.

The party, currently headed by the media-savvy but loose-lipped Leo Varadkar, the Irish Taoiseach, has its origins in the party that accepted temporary British dominion status after independence in 1922.

For that reason, Varadkar dare not be seen as caving in to British insistence that the UK can be simultaneously in and out of the EU in Northern Ireland.

Irish politics matter

Fianna Fail, the strong opposition party hoping to seize power, is pushing for an early election and with the help of other parties in the Dail may get their way.

In the north, the stand-off between the Democratic Unionist Party (DUP) and Sinn Fein refusing to share power in a joint government means that there is no government in place in Northern Ireland with any leader that is capable of thinking beyond internal party politics or personal political survival.

Varadkar and Dublin can veto all of London’s hopes next month even if the EU plans to agree to move ahead to trade talks in 2018 in order to avoid crashing over the Brexit cliff.

Varadkar has to deliver a “no border” deal in order to survive in power — he leads a minority government after all. For that reason, he has no flexibility regarding the demand that Mrs. May pledge in writing that today’s border arrangements will be maintained.

And if an early election is called in Ireland, the prospects for the Tories to overcome the Ireland hurdle don’t become any better. In a campaign, both of Ireland’s main parties will be forced to step up their anti-London line on Brexit in order to defend the Peace Agreement.

The only logical way out is for the UK to drop the ideological insistence among hardline Brexiteers on leaving the Customs Union.

The issue was barely raised in the Brexit debates before the referendum and certainly did not feature on the ballot paper. The UK can leave the EU, but still stay in the Customs Union.

British politics interfere

But here English politics, like Irish politics, enters the story. May has given Liam Fox a brand new department for International Trade. It has delivered nothing except air miles for Fox.

This department should logically be merged with the Department of Business or even the Foreign and Commonwealth Office (which sees its income cut from £2bn to £1.2 bn over next 2 years under the new budget).

Liam Fox should be given some other cabinet post so as not to lose face.

Mrs. May also depends on Northern Ireland’s homophobe creationist DUP – ultra-hardline Protestants who are enjoying being in the limelight as the 10 MPs who give Mrs May her working majority.

Of course, the DUP is dead set against any concessions to Dublin. Left to its own devices, it wants to use Brexit to unmake the Peace Agreement.

Labour to the rescue?

Can Labour work to save the Peace Process which will take a fatal hit if border control check points return to re-create a physical border in Northern Ireland?

Can Labour press Mrs. May to send a signal that would be universally welcomed by business in all corners of the British Isles?

What is needed, not just for companies’ sake, is that — whatever final form Brexit takes — the UK will stay within the Customs Union for at least as long as Brexit-related passions between Leavers and Remainers die down and a common-sense solution can be found.

Denis MacShane is the UK’s former Minister for Europe and a Senior Advisor at Avisa Partners.