Chatham, United Kingdom - For hundreds of years, ships set sail from Chatham's Royal Dockyards to extend and enforce British power and influence around the globe. Now the world has come to Chatham.

Shop fronts on the southern English port town's busy high street advertise foods from Romania, Bulgaria, Poland and Turkey and SIM cards offering cheap international calls, while halal butchers and kebab grills vie for customers alongside traditional pubs, fish and chip shops and Indian and Chinese takeaways.

Such cultural diversity has become commonplace in many British towns since 2004, when the expansion of the European Union brought an influx of workers from Poland and other central and eastern European countries.

Emil, a teenage Roma boy born in the Czech Republic, moved to Chatham with his family eight years ago, having been brought to the UK by his parents as a toddler. Since leaving school he has found work in a greengrocer's shop and dreams of one day running his own fruit and vegetable business.

"It's better here. In the Czech Republic you can't really earn enough money to enjoy life. Our people have nothing," he said. Like most migrants that Al Jazeera spoke to, Emil did not want to give his full name.

But, five months away from a general election in which immigration has become the dominant issue, Emil and migrants like him find themselves squarely in the crosshairs of politicians who say that Britain has lost control of its own borders.

Figures published last month revealed an increase of 78,000 in net migration to the UK - bringing the total up to 260,000 for the year ending in June 2014.

The figure was an embarrassment for David Cameron, the British prime minister, who had pledged to reduce it to under 100,000 by 2015.

Meanwhile, right-wing newspapers have been despairing over the country's growing dependency on cheap imported labour, with the populist Daily Mail wondering in a front page headline, "Can no one in Britain make a sandwich anymore?" after a catering company was forced to go to Hungary in search of new staff.

When I came I expected to stay for one year, but now I have my own business. There's a lot of paperwork but I am working for myself. I can't see Britain leaving the EU because it would be suicidal. London is the business capital of Europe. - Mariusz, Polish immigrant

Immigration crackdown

Last month voters in Rochester and Strood, the parliamentary constituency that includes areas of Chatham, elected a candidate standing for the anti-immigration UK Independence Party (UKIP), which wants Britain to withdraw from the European Union.

The victory was UKIP's second in weeks, both following byelections triggered by defections by members of parliament from Cameron's right-wing Conservative Party. The party also finished first in May's European elections, gaining 28 percent of votes.

Asked during the campaign whether nationals from other member states would be allowed to stay if the UK left the EU, Mark Reckless, UKIP's winning candidate, suggested they would only be allowed to remain for a "fixed period". The line was later clarified by UKIP that said it did not favour enforced repatriation, but opponents claimed that Reckless had let the party's mask slip.

Emil admits the tone of the immigration debate, and the prospect of the UK withdrawing from the EU, has left him worried for his future. "I've been here all my life and I just want to work. I don't know anything about the Czech Republic. If they sent me there I don't know what I would do."

But it is not just UKIP that is talking tough about immigration. With the subject consistently topping a monthly index of issues of concern to voters, mainstream party leaders have also been scrambling to establish their own credentials.

In a speech last week, Cameron said migrants from the EU would have to work for four years to become eligible for benefits and said those who did not find a job within six months of arriving would be forced to leave.

Cameron, who has promised a referendum on EU membership if re-elected, hinted he could even campaign for the UK to quit the bloc if other countries refused to renegotiate migration rules.

Ed Miliband, the leader of the centre-left opposition Labour Party, has also pledged to introduce restrictions on migrants' rights to benefits, and to protect British jobs by banning firms from recruiting exclusively abroad.

Yet among migrants in Chatham there is concern that the positive benefits of immigration may be forgotten in the clamour for tougher border controls and a crackdown on so-called benefit cheats.

"David Cameron is just looking for an immigration problem, but there are lots of English people who don't work, who take lots of benefits and who drink alcohol on the streets," said Mariusz, a Pole living in the UK since 2004.

He said many migrants had moved to Chatham and other small towns in southeastern England with traditionally small ethnic minority populations because living costs were significantly lower than in London.

"When I came I expected to stay for one year, but now I have my own business. There's a lot of paperwork but I am working for myself. I can't see Britain leaving the EU because it would be suicidal. London is the business capital of Europe."

The media blames immigrants for crime or calls them benefits cheats, but what about the rest? Why are they not saying that they are growing the economy, opening shops and businesses? If you want to reduce the number of bad people then you have to have the correct system. - Mohammad, Iranian immigrant

'Nothing for me here'

But not every migrant has a success story to tell. Ajab, originally from the Kurdish region of Iraq, said he had been in the UK since 2003 but had not been able to find a secure job and worked occasional days at a car wash to survive. He said he did not claim benefits because he does not read or write English and plans to follow many Kurdish exiles back home soon.

"There is nothing for me here," he said. "I go home and sit there. Go out, walk about and then home, same. Nowhere to go."

Mohammad, an Iranian living in the UK for 12 years, said he believed the benefits of immigration outweighed the negatives "70 to 30".

"The good immigrants have helped this country because we work hard, we establish families, we buy a house and we help the economy. But if you want immigration then you have to take the good and the bad people," he said.

"The media blames immigrants for crime or calls them benefits cheats, but what about the rest? Why are they not saying that they are growing the economy, opening shops and businesses? If you want to reduce the number of bad people then you have to have the correct system."

Recent research by academics at the Centre for Research and Analysis of Migration at University College London supports Mohammad's belief that immigration has benefited the UK economy.

They calculated that European migrants had made a net fiscal contribution of more than £20 billion ($311bn) to UK public finances between 2001 and 2011 and contributed significantly more in taxes than they claimed in benefits.

Yet with public services squeezed by government spending cuts and many British people struggling to hold onto their jobs and meet fast-rising housing costs, many question whether current rates of migration are sustainable or beneficial.

"If you start to go down any road of discrimination it is no good for society as a whole. Because people are very easily manipulated," said Jean Waller, a retiree.

"Once people are here and you've accepted them I don't think anyone should leave. I think there may be a problem because there are so many people allowed in, because there aren't enough jobs as it is. They have to do something, but I don't know what the answer is."

Breathing new life

For now, many in Chatham say migrant-run businesses are breathing new life into a high street blighted by three decades of economic decline since the closure of the dockyard in 1984, a major shipbuilding hub.

Ghani, a shopkeeper originally from Pakistan, said the high street had improved even in the five years since he had moved there from London. "I didn't see a lot of non-British people then. Now they are regenerating the area."

Azam came to the UK from Kashmir 37 years ago. Now retired, he spent most of his years working in a local factory. "This is dead now. You see a lot of people doing nothing," he said, gesturing at boarded-up store fronts.

"But we've got four fruit shops now and I don't know how they are doing it but they're not shutting down. They open at eight in the morning and they close at eight at night. I mean, no Englishman would do that."

But Azam said he feared for the prospects of those still coming to the UK with dreams of building a better life.

"I've got nothing against those people because I was an immigrant myself, but there's not enough jobs any more. It's hard work, my friend, hard work and nothing else."

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