Boris Johnson has said migrants who live in the UK but cannot speak English are oppressed. The London mayor stated everybody who moves to the UK should speak the language so they can integrate. He said he favours the culture of the US, where schoolchildren are required to pledge allegiance to the flag every day before school begins.

"The crucial thing for me is that everybody has to speak English," Johnson said at the CityLab conference in Central London. "That's absolutely central to our identity, to our culture. And for my money, it's a form of oppression if people who have lived here for decades are actually unable to speak English and to participate in the economy.

"I find that most people actually, when they come here, desperately want to belong, and understand this country and its culture and its history. We shouldn't be shy. We shouldn't be embarrassed about teaching that in our schools, and pushing it up the agenda."

Talking about the US, he said: "There's a sense of wherever you have come from, whatever your previous identity was, you have become American. You have become part of that strong, charismatic political identity. I think we're getting there in this country, but there was a long period in the 70s and 80s when we kind of let all that go and we led a multicultural endeavour."

According to the 2011 census, 863,000 people living in England and Wales said they could not speak English well or at all, around 2% of the overall population. The current government has cut funding for English language courses for migrants.

The number of foreign-born people living in outer London increased by 96% between 1995 and 2013, according to the Oxford Migration Observatory. As of 2013, there were 2.8 million foreign-born people in London, or 34% of the city's population. For the UK as a whole, 12.5% was foreign-born.