It was not so long ago that London was inaccurately described as "Londonistan," owing to the number of political exiles from the Muslim world, including Arab Islamists, present in the British capital. Many of them returned to their home countries in the aftermath of the Arab uprisings in 2011, but the trend is cycling back. Egyptian Islamists in particular have fled to the United Kingdom after the overthrow of Islamist President Mohammed Morsi in July — but the world has changed. British Prime Minister David Cameron ordered an investigation of the Muslim Brotherhood March 31, following accusations the group was terroristic in nature.

What are the national, regional and international implications of such a move? Has the UK really changed that much?

Islamists have been coming to the UK for many years, dating back to the beginning of modern political Islamism. Arab Islamists sympathetic to or members of the Muslim Brotherhood started arriving as students from different countries in the 1970s and 1980s, and those that decided to stay began civil society organizations. Many of these nonviolent groups developed into essentially post-Islamist organizations, focused more on indigenous British concerns, as opposed to following issues in the Arab world.

It was not only Brotherhood-style Islamists who came. Far more radical Islamists did as well, later on. The likes of radical clerics Abu Qatada, Abu Hamza al-Masri, Omar Bakri Muhammad and others made their homes in London, much to the consternation of other European governments. The French in particular were furious that such radicals could live freely in London, while their British counterparts essentially argued that as long as such extremists did not break British law on British soil, they were free to remain. These more radical Islamists interpreted this as a "covenant of security" — the UK would be considered off limits from attacks from their ilk.