Romford, England - Romford market, on a cold grey June morning. England flags flutter in the breeze, traders and customers chatter in a friendly way.

I've come to this commuter town east of London because polling suggests it's the most Eurosceptic - meaning hostile to the European Union - of any in the United Kingdom.

My own, very unscientific, sampling of opinion in the market suggests Romford's reputation as a bedrock of support for the "Vote Leave" campaign is deserved.

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Dave Crosby, a fishmonger who sells jellied eels, cockles and whelks, tells me the EU ("pen-pushers in Brussels who've not even been elected") has ruined the British fishing industry through imposing quotas favouring foreign fishermen.

Others are less considered. One man wearing a "Vote Leave" badge tells me: "Angela Merkel's won this war without even firing a gun."

Another, elderly man, who says he fought in World War II, is disgusted with Prime Minister David Cameron, who cares more "about men in turbans and skirts than he does about veterans".

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The comments, and the vehemence with which they're expressed, suggest just why calling this referendum may prove such a disastrous mistake by Cameron, whose Conservative Party has belittled and ridiculed the EU for decades, but who is now fighting desperately to convince Britain to stay in.

In part, the opinions I hear on the streets of Romford evoke that old cliche about Britain being a country that lost an empire and is still searching for a role.

But there's something else going on here.

I sense a strong desire from people to give those in power a metaphorical bloody nose. And that, of course, is part of the problem with referendums. They ask a specific binary question, in this case Remain or Leave, but the voters may have all sorts of motivations beyond the question itself in making their choice.

Who was it, after all, who dismissed referendums as "a device of dictators and demagogues"?

Yes, she of sainted memory to British Conservatives, Margaret Thatcher.

'Great again'

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The "Vote Leave" campaigners have understood this better than their rivals in "Vote Remain".

Their message is simple, populist and at times grossly misleading, but it conveys both nostalgia and a sunny optimism about what Britain can be in the future.- Britain, I was told on the streets of Romford, can be "great again".

The local Conservative MP, Andrew Rosindell, a passionate supporter of "Vote Leave", told me that "people are proud of our Queen, our traditions, our armed forces and our flag", and feel that these are under threat from the EU.

There's no evidence of such threats, but that's not the point. It chimes with people's mood here; that things were once better, that they're being cheated by those in power.

It's the same feeling which enables the "Vote Leave" campaign to dismiss warnings from respected economists, academics and diplomats as to the costs of Brexit: all are contemptuously lumped together as "experts", apparently a term of abuse.

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But there's another way in which "Vote Leave" have succeeded. They've managed to steer the argument time and time again to immigration, an emotive and sensitive subject, and one which the British establishment finds awkward to contest.

If Britain votes to leave the EU (and as I write that's what the polls are suggesting), we'll look back on May 26 as a defining moment in this campaign. That's when the 2015 immigration figures were published, and they showed a net inflow of 330,000. It was a hammer blow to a prime minister who has promised for years to bring that number down to five figures.

Britain, says "Vote Leave", has to "take back control of its borders", and this is impossible as long as it's obliged to respect the freedom of movement that is an essential aspect of EU membership - the inconvenient truth that just over half of these 2015 migrants came from outside the EU is brushed aside.

Immigration, argues "Vote Leave", is putting an intolerable strain on schools, hospitals, housing and roads, and it's the poorest parts of British society who are paying the highest cost.

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"Vote Remain" politicians have responded in an incoherent way; they hesitate between trying to explain the benefits of immigration, arguing that it can be controlled within the EU, or pointing out that leaving the bloc may make little difference to the numbers in any case.

They're dismayed at what they're discovering on the doorsteps; to many British voters, the referendum on EU membership has morphed into a plebiscite on immigration.

All of which is good news for Nigel Farage, the leader of UKIP, a political party that is dedicated to taking Britain out of the EU and which won almost four million votes in the 2015 general election.

One day last week I watched Farage as he rode past parliament in Westminster on top of an open double-decker bus emblazoned with a huge picture of his own face. He waved and grinned as passing motorists beeped their horns in support.

Behind him was a convoy of vans displaying posters. "Breaking Point" they said in big letters superimposed over a photograph of refugees trying to enter Europe, "the EU has failed us all".

The posters shamelessly conflate the refugee crisis, which will surely carry on whatever Britain decides on June 23, and the debate about freedom to migrate within the EU.

And, to put it mildly, they don't appeal to voters' more generous or braver instincts.

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I was watching Farage's convoy drive past when I got a call from the Al Jazeera newsdesk. An MP had been attacked, I was told, shot and stabbed, on the streets of her constituency in northern England.

I was soon on my way to Yorkshire.

The killing of Jo Cox, a rising star of the Labour Party who'd campaigned for a more generous approach to refugees, is an extraordinary and horrible event that has shocked people of all political persuasions, just days before the referendum.

The suspect, when asked to give his name in court, replied "Death To traitors, freedom for Britain".

Politicians have been understandably reluctant to even speculate on whether it's in any way connected to the looming vote, or whether it might affect the result.

But it seems legitimate to pause and ask at least one question: has politics in this country ever been this ugly?

Source: Al Jazeera