British Foreign Secretary Boris Johnson set out his plans for a "glorious" Brexit on Saturday that angered colleagues and reignited speculation he would challenge Prime Minister Theresa May for the leadership of the Conservative party.

With May due to set out her vision for Brexit in a speech in the Italian city of Florence on Friday, Johnson published a 4,300-word newspaper article that roamed well beyond his ministerial brief and, in some cases, went beyond the approach set out by the government.

Britain, he said, would not pay to access European markets in the future. Once out of the European Union, the country should borrow to invest in infrastructure, reform the tax code and set immigration levels as it sees fit.