An unpublished article in which Boris Johnson pledges his allegiance to the Remain campaign, written days before he came out in favour of Brexit, is causing a spot of bother.

He claims that it was “semi-parodic”, but does admit that he was “wrestling” with whether to back Brexit.

Johnson is now seen as a backer of a “hard Brexit”, this week insisting the UK can get a trade deal that is “of greater value” to the economy than access to the EU single market – which he described as an “increasingly useless” concept.

But in the pro-EU article, revealed in a new book and published in The Sunday Times, he supported membership of the free trade zone.

Boris Johnson
(Mary Turner/AP)

Discussing the article with Sky News, Johnson said: “Everybody was trying to make up their minds about whether or not to leave the European Union and it is perfectly true that back in February I was wrestling with it, like I think a lot of people in this country, and I wrote a long piece which came down overwhelmingly in favour of leaving.

“I then thought I better see if I can make the alternative case for myself so I then wrote a sort of semi-parodic article in the opposite sense, which has mysteriously found its way into the paper this morning because I think I might have sent it to a friend.

Boris Johnson.
(Ben Birchall/PA)

“But I set them side by side and it was blindingly obvious what the right thing to do was, and I think the people made the right decision, they voted very substantially to leave the European Union, that is what we’re going to do and we’re going to make a great success of it.”

On Saturday sources close to the Foreign Secretary repeated that he wrote the article for the sole purpose of trying to articulate in his mind whether there was any merit in the Remain argument, and dismissed it out of hand as soon as he finished.