A return to Londonistan?
The widely acknowledged failure of the Arab Spring uprisings to deliver democracy to the Middle East is reverberating here in Britain.
With a backlash under way by some Arab governments against their opponents, such as the Muslim Brotherhood, could London once again become a haven for Arab dissidents bent on removing their own governments, as it was in the 1990s?
French intelligence officials had a contemptuous word for our capital back then. They called it "Londonistan".
It was a reference to the plethora of Middle Eastern and North African dissidents plotting the downfall of secular governments in countries like Egypt, Yemen and Algeria.
Most were peaceful, but some were radical extremists with links to violent groups overseas - even Osama Bin Laden openly kept a PR operation in London - the "Advice and Reformation Committee" - with its own PR rep, a Saudi national since extradited to the US.
Yet for years the Home Office, the Metropolitan Police and MI5 all largely turned a blind eye, believing that by providing a "covenant" of protection, Britain itself would be safe from attack.
The London bombings disproved that.
Fast forward a decade and clearly there is some head-scratching going on in Whitehall about just what Arab opposition activists are up to on British soil.
On 1 April, Prime Minister David Cameron ordered a review into the activities of the Muslim Brotherhood after unsubstantiated reports that some of its leaders were linked to terrorist attacks in Egypt.
"There's always been a sort of historical constellation of people within the UK who are involved with political activism in foreign countries," said Raffaello Pantucci, an expert on extremism at the Whitehall think tank, the Royal United Services Institute (RUSI).
"The element that's changed now is the fact that people now look at those groups with an element of suspicion as well.
"I think previously there was a sense that they were allowed to operate here and it wasn't a huge concern but now, given the links that we see to other terrorism that has taken place in the United Kingdom that has emerged in this broader community, they are watched a lot more carefully and this makes it much more difficult for them to operate abroad."
But hang on, surely Britain is meant to be a haven of free speech and democratic ideals?
With democracy largely denied in the Arab world, is it not a credit to the UK that peaceful opponents of unelected regimes should choose London as their base?
And is there not a risk in Britain of driving harmless dissidents underground and into the arms of extremists?
'Fight against terrorism'
Saleh Magaache is an Algerian dissident living in London and he welcomes what it offers.
"Politically, London is a good space for all the political people to move around and express themselves without any pressures from dictators, or some political pressure from back home.
"It's good access to all the UK officials."
So when does freedom of speech cross over into illegal activity? I put the question to David Anderson, the Independent Reviewer of Government Terrorism Legislation.
"There's a test that always has to be satisfied," he said.
"The group must be concerned in terrorism. It's a very broad test, it applies really to any group that is violently opposed to any government in the world.
"To narrow it down, the home secretary applies her discretion and she'll look at a number of factors: she'll look at where the terrorism has been taking place, she'll look at how strong the presence of the group is in the United Kingdom, and very importantly, in many cases, she'll look at the solidarity with other countries in the fight against terrorism."
The trouble is, Britain's definition of who constitutes a threat to society has frequently failed to match the views of its conservative Arab allies overseas.
For years the Egyptian and Yemeni governments complained to Britain about the activities of radical cleric Abu Hamza al-Masri.
But it was not until 2004 that he was finally arrested and imprisoned on a US extradition warrant - he was jailed in the UK in 2006 for inciting murder and racial hatred and extradited to the US in 2012 where he is currently on trial facing 11 terrorism charges.
In Cricklewood, north London, a Saudi dissident continues to live freely while his own government back home designates him a terrorist.
And in the wake of the Arab Spring, rulers in the United Arab Emirates have complained loudly about the Muslim Brotherhood, which they see as a threat to their rule - and many of whose members live in Britain.
"There are plenty of cases in which other countries have banned organisations and would like us to do the same," said David Anderson added.
"And we certainly don't go along with that in every case. We have to be satisfied that the statutory test (on terrorism) is met."
Ultimately, the question is now whether Britain has got the balance right, knowing when it is time to close down those who propagate hatred or violence, and when to permit peaceful free speech, however much that might be anathema to some governments in the Middle East.
In a statement sent to the BBC, the Home Office said it was looking to improve ways of tackling terrorism and extremism, including deportation and depriving people of citizenship.
"Coming to live in the UK is a privilege that we refuse to extend to those we believe are seeking to subvert our shared values and represent a threat to our society," a spokesman said.
So have the lessons from past mistakes been learned?
Mr Pantucci thinks a return to the days of Londonistan is unlikely. "Since the 1990s we have seen a shift in that perception and analysis of these groups. You've seen that there is still a lot of activism that goes on in this country so elements of Londonistan do persist," he said.
"However, I think that the sort of open radicalisation and recruitment that we used to see, its difficult to see that re-emerging again in such an open fashion."