Mary Dejevsky: Foreign policy should not be dictated by exiles living here

If you had been in Whitehall on Monday evening, you would have witnessed a quaint, even charming, scene: men in dinner jackets and women in evening gowns picked their way cheerfully through the labyrinthine road works that currently disfigure this stately London street.

But it wasn't the roadworks that had pedestrianised Whitehall for several hours, it was a demonstration by the city's Tamil population, protesting about the bloodshed among their compatriots in Sri Lanka. They had broken out of Parliament Square, where a fluctuating group has been demonstrating for more than a month now, and four of them had scaled Westminster Abbey.

Now I know that utterly terrible things are happening in Sri Lanka, where government troops are trying to crush the remnants of the Tigers – and extinguish Tamil hopes for an independent homeland. And I have great sympathy, as very many Britons do, for other people's aspirations for independence – especially when, as in the Tamils' case, they are so far outnumbered and outgunned.

Yet the Tamils' London protest, now entering its sixth week, poses two questions that go way beyond the exotic sight of crinolines in Whitehall. The first relates to protests; the second to British foreign policy.

The protests first. To demonstrate in and around Parliament these days, you need permission. You can agree or disagree with this, and I disagree – strongly. In a democracy people should not need a permit to protest outside Parliament. Our elected representatives should have to see and hear what even a tiny section of the people think.

Yet a particularly kid-glove approach seems to have been applied to the Tamils. We know how the G20 demonstrators were treated in the City. And you may recall how, in 2005, a couple were arrested for trying to read out a list of Britain's Iraq war dead in Whitehall. But the Tamils, who initially had no permit to protest, received one retrospectively, and apparently it has no time limit.

Over the weeks, the disruption in that part of London has been huge. Monday was not the first time that thousands of people must have been mired for hours in long and almost static diversions. This has a cost, to individuals and the economy. But not, it seems, to the police, who told me that policing the Tamil protests fell "well within the usual resources". What does that say about "usual resources"?

Now you can argue that it is beyond mean to juxtapose the life and death concerns of Tamils with a spot of local inconvenience. And you could say that traffic jams caused by protests in Westminster are a price Londoners should be willing to pay – a sort of humanitarian support tax in kind. You may also speculate that the Met's tactics are a reaction (over-reaction?) to criticism of the way it policed the G20 protests. Even so, five weeks is a lot of disruption; and ample opportunity to get your message across.

The Tamils' message, though, is not intended just for you and me. It is intended for the Government. The protesters want ministers to put pressure on the Sri Lankan government to halt the bloodshed. In effect, they want Britain to use what they see as its clout abroad to influence the outcome of someone else's civil war.

Which poses the second, and wider, question. How far should any government allow its foreign policy to be swayed by vocal exiles representing families, and causes, they have left behind?

The reasonable answer would surely be: not at all. Yet since the protests began, the foreign secretary has tried (and failed) to send an envoy to Sri Lanka. He has visited Sri Lanka himself, where he may or may not have given his opposite number a hard time. And this week he convened a meeting on Sri Lanka at the UN. Have London's Tamils already skewed British policy to the point where it is helping to prolong a nasty civil war and indulging a force (the Tigers), which is proscribed here for terrorist associations?

Efforts to influence policy are not unique to Tamil exiles. There are councillors, even MPs, whose election may depend on taking the "right" line over Kashmir. Exiled oligarchs have tried, with some success, to obstruct better British relations with Russia. While some exiles will never be deterred from trying to affect events where they came from, co-opting their new country in their old cause should be another matter.

m.dejevsky@independent.co.uk