Britain’s Prime Minister Boris Johnson helps quality control staff during a general election campaign visit to the Tayto Castle crisp factory in County Armagh, Northern Ireland, Britain November 7, 2019. Daniel Leal-Olivas/Pool via REUTERS Daniel Leal-Olivas/Pool via REUTERS

UK Prime Minister Boris Johnson just accidentally made the perfect argument for remaining in the European Union.

Speaking in Northern Ireland, Johnson said his proposed Brexit deal would allow the province to keep free movement and access to the European single market and described this as a „great deal.“

These benefits, however, will be lost by the rest of the United Kingdom.

This prompts the obvious question as to why his deal denies this to the rest of the UK.

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UK Prime Minister Boris Johnson made an unusual and very revealing comment Thursday night that inadvertently serves as an incredibly compelling argument against his own Brexit deal.

Speaking at a meeting of local Conservatives in Northern Ireland on Thursday evening, the prime minister said: „Actually, Northern Ireland has got a great deal. You keep free movement, you keep access to the single market, but you also, as it says in the deal, have unfettered access“ to Great Britain.

This poses a rather obvious question.

If retaining free movement and staying in the European single market is such a „great deal“ for Northern Ireland, then why has Johnson prioritized a Brexit plan that would prevent the rest of the United Kingdom from having that same access and freedom?

„The Single Market and freedom of movement are a great deal — even Boris Johnson recognises this — so why isn’t he keeping them for the whole of the UK as part of the many benefits of EU membership?“ Liberal Democrat MP Tom Brake said Friday morning.

Watch Johnson accidentally argue against his own Brexit deal

Tweet Embed: //twitter.com/mims/statuses/1192694594892382208?ref_src=twsrc%5Etfw „Northern Ireland has got a great deal. You keep free movement. You keep access to the single market.“ pic.twitter.com/GMFvbJvJ5n

The Brexit deal Johnson brokered with the EU in October would see the UK leave both the single market and the customs union while also ending free movement and replacing it with a „points-based“ immigration system similar to Australia’s.

The prime minister insists this deal would see the UK „taking back control of our money, our laws, and our borders.“

Northern Ireland, however, would remain wedded to EU customs and single-market rules to preserve its invisible border with the Republic of Ireland.

Analysis by the National Institute of Economic and Social Research suggests it would make every person in the UK £1,100 poorer a year on average. The independent forecaster found the prime minister’s withdrawal plan would leave the UK £70 billion, or about $90 billion, worse off a year and shave nearly 4% off the economy by the end of the 2020s.

Most of that lost output would be directly caused by trade barriers arising from the UK’s decision to leave the single market and customs union, which is exactly why Johnson appears to be arguing that Northern Ireland’s exemption from this is beneficial.

His comments are also a gift to the Scottish National Party.

Scottish First Minister Nicola Sturgeon, whose SNP party is launching its own election campaign on Friday, will now surely argue that if staying close to the EU is such a „great deal“ for Northern Ireland, then why can’t all the other nations of the UK be given this deal too.