The 1,037 words that may have brought down Boris Johnson

Boris Johnson has announced he will not run for the leadership of the Conservative party.

The UK media had been called to a press conference Thursday morning in which they expected to hear Boris announce his leadership campaign. Instead, they got one of the biggest political upsets in the last week.

In a statement Boris outlined the agenda for the next prime minister of the country, and then said of his role in the leadership race:

Well, I must tell you, my friends, you who have waited faithfully for the punchline of this speech, that having consulted colleagues and in view of the circumstances of Parliament, I have concluded that person cannot be me.

My role will be to give every possible support to the next Conservative administration.

The news comes swiftly after his Vote Leave campaign colleague Michael Gove announced his bid for the party leadership with this line:

I have come, reluctantly, to the conclusion that Boris cannot provide the leadership or build the team for the task ahead.

The news has caused shockwaves in Westminster, but today's speech from Boris may not have been the words that sealed his fate.

Boris was widely criticised for his weekly column for the Telegraph on 26 June, headlined "I cannot stress too much that Britain is part of Europe – and always will be", in which he set out a vision of leaving the EU that looked suspiciously like staying in Europe.

He promised a version of free movement, which he later retracted in a statement after it angered the Conservative right and Leave voters.

I cannot stress too much that Britain is part of Europe, and always will be. There will still be intense and intensifying European cooperation and partnership in a huge number of fields: the arts, the sciences, the universities, and on improving the environment. EU citizens living in this country will have their rights fully protected, and the same goes for British citizens living in the EU.

British people will still be able to go and work in the EU; to live; to travel; to study; to buy homes and to settle down. As the German equivalent of the CBI – the BDI – has very sensibly reminded us, there will continue to be free trade, and access to the single market.

Many picked up on promises that were probably optimistic negotiations for a post-Brexit UK:

Soon there were lines being circulated that Boris had not performed to the best of his ability:

Now people are claiming that this announcement he will not stand for the leadership can be traced back to the column.

What a time to earn £250,000 a year.

More:Remembering what Michael Gove said one month ago about being Tory leader

More:This letter about surgeons and Brexit makes a very interesting point