LONDON – Last week's terror attack by a British-born Muslim proves again that a radical community exists within Britain. Its goal: create an Islamic nation. And there is a quieter force at work that will likely achieve that desire long before guns, bombs and violence.

This is not Karachi. It's London.

Britain's policy of mass immigration has brought what one expert calls "demographic upheaval" to the United Kingdom that could change almost everything.

"Finis Britanniae" – The End of Britain

It's now a demographic certainty. Someday the white native English will be a minority in their own country, including the native Welsh and the Scots.

It's just a matter of when.

Professor David Coleman is a supernumerary fellow in human sciences and university professor in demography at Oxford. He's has written that uncontrolled immigration could lead to "finis Britanniae."

"Which simply means the end of Britain, and by that, I mean the end of Britain as we know it," Coleman said.

"The point I was making is the change in the number of people and particularly the change in the origins of people, in their religion, in their cultural background, would make Britain unrecognizable compared with the present time," he said.

Immigration can strengthen a nation. But several western nations, including the United States, are debating the wisdom of large-scale immigration from the Islamic world. And experts wonder what will happen as Muslim numbers continue to grow in officially Christian Britain.

In the dystopian masterpiece Children of Men, ethnic division and civil war wracks Britain in 2027. Armed Muslim gangs fight a government that is hunting down and deporting immigrants while trying to maintain order.

Britain's future is not likely to be this violent, but it may not be peaceful either.

When the Christian activist group Britain First took large crosses through Luton's Bury Park last year, angry Muslims confronted them.

MUSLIM MAN: It’s our country.

WHITE MAN: It’s your country, is it, yeah?

MUSLIM MAN: Yeah mate, it’s our country.

WHITE WOMAN It’s a Christian country.

MUSLIM MAN: It’s not a Christian country.

WHITE WOMAN Yes it is.

MUSLIM MAN: It’s not a Christian country, mate....You’re jealous. You’re jealous that we’re taking over.

MUSLIM WOMAN: The Muslims will take over. Watch.

Urban areas are becoming increasingly Islamic whereas rural area are becoming increasingly English, and there's a retreat away from these two populations. That's the future.

Policy analyst George Igler says he does believe it will take 40 or 50 years before the native British are a minority.

"This is a nonsense. It's going to be much sooner. And more importantly, when you look at places like Luton. When you look at the experience of women in Cologne. We already have a window into what this future will be like. It's going to violence and sexual violence against non-Muslims. It's going to be insistence on Sharia Law," Igler said.

Drastic Changes on the Horizon

Professor Coleman, who stressed he is not anti-Muslim but is simply looking at statistics, nevertheless said the changes could be drastic.

"There are strong currents in Muslim society which wish to see Muslim approaches to diet, to marriage and would like to see Sharia Law incorporated formally into British Law or in respect to some extremist groups would like to see Sharia Law replace British Law," he said.

More than a half million non-British citizens immigrated to the United Kingdom in 2016. European Union rules prevented Britain from stopping migration from within Europe, but that brought European migrants.

Coleman says Brexit, Britain's exit from the E.U., will not necessarily stop the influx of immigrants from non-European Islamic nations.

'England Is Not Going to be England Anymore'

Great Britain was a factory for Muslim terrorists long before last week's attack on Westminister Bridge by a British-born Muslim. At least 850 British citizens have left the U.K. to join ISIS.

"Look, we have around 100 Sharia courts in this country. We're the only western country with a functioning network of Sharia tribunals and councils. They're dealing with marriages, divorce, even with criminal matters. They're marrying children," said Anne Marie Waters, from Sharia Watch.

If demographic trends continue, British schools will change when most of the pupils are from non-British backgrounds, as will British foreign policy and military alliances.

"England is not going to be England anymore," Igler says.

In its street protests against the Islamization of Britain, the English Defence League used to sing 'we want our country back.' If current demographic trends continue, it may be too late for that.