The repercussions will echo down through the years, affecting British politics, immigration, attitudes to Europe, possibly the survival of Britain as now constituted, and the social progress of Asian and African minorities there where immigrants now comprise 11.9 per cent of the population.

These things, which were in flux, may now transit to turmoil. And Prime Minister David Cameron's differences with his own Conservative Party could lead to his ousting, unless he can use the murder as a kind of call to order in his rebellious ranks.

There are two big but related issues that have already roiled British politics and now may be forced to a head. The first is immigration. Always a thorny issue for Conservatives, it has been front and centre since a big victory in local elections this month by the upstart United Kingdom Independence Party (UKIP) led by Nigel Farage.



Farage's platform is anti-immigration, not only from Africa, Asia and the Caribbean but also from the European Union. He calls for Britain to leave the EU and essentially seal Britain's borders against all comers. UKIP's local government success led backbench Conservatives - more than 100 of them - to seek an immediate referendum on Britain's leaving Europe. They were joined in support by Tory grandees, who had previously supported the Prime Minister.

One way or another, things will be harder for immigrants, no matter when their families arrived in Britain. These divide essentially into long-time immigrant groups from Africa, Asia and the Caribbean - and Eastern Europeans, allowed in as a result of EU labour laws.

There is also a sharp division between Muslim immigrants and those who practise other religions. Muslim immigration has grown to the point of domination in some areas - such as Bradford, in the north of England, and Birmingham in the Midlands. Muslim immigrants - now 4.8 per cent of the population, and Islam the second-largest religion after Christianity in Britain - have established states within their adopted state with Islamic education, very visible mosques, and a palpable sense of their homelands being where they came from ancestrally, rather than where they live now.

The internet and mobile phones have made this duality easier to practise. Sadly, the Muslim community in Britain has prospered far less than the Hindu community, where millionaires and some billionaires abound.

British resentment of the Muslims extends to the treatment of women, halal slaughter of animals, instances of honour killings and many foiled terrorist plots since the subway bombing of 2005.
In Qatar, I ran into a young English Muslim woman wearing a veil and dressed in traditional Arabic clothing. Hearing her speak, I said: ''Hi, you're English.'' She rounded on me, replying angrily that although she was born and raised in England, that did not make her English.

Understandably, this active refusal to assimilate breeds resentment among the Anglos. The trouble is everyone of colour is assumed to be Muslim in the eyes of many of the Anglos, and the working class in particular. Hence the rise of right-wing extremists, such as the skinheads and the fascistic British National Party, and the more seductive UKIP. The Labour and Liberal parties are sidelined for now, without the visceral appeal that the Tories feel they may have ceded to the UKIP.
Meanwhile, there is another shadow on the horizon: Scottish nationalists may push their own referendum on whether to leave the United Kingdom. Their leader, Alex Salmond, sees trouble in the south as opportunity in the north.

If things go really badly, Cameron could be seen in history as the prime minister who lost both Europe and Scotland - or rallied the country and saved the day.
The murder in Woolwich, ghastly in its barbarity, will have consequences beyond that place.