The public believes that the Government should ban immigrants from taking jobs while a million British youngsters are unemployed, a new poll for The Independent on Sunday has found.

As David Cameron and Ed Miliband attempt to finalise their policies on Europe, immigration and employment before the next election, the ComRes survey has revealed a hardening in voters' attitudes to the issue of "British jobs for British workers".

Three-quarters of the public think that it is wrong for the UK to recruit from overseas while a million young people are struggling to find jobs – although one in three accept that businesses can't be blamed for looking abroad "because too many British workers are lazy".

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Two-thirds of those questioned think that British firms should give UK citizens priority over other candidates from elsewhere in Europe when hiring new workers – even if this means Britain having to leave the European Union. Just 16 per cent disagreed.

The stance on immigration has changed radically in the past four years, as Britain has struggled with deepening recession and strained relations with its EU partners. In 2009, almost six in 10 people agreed that all citizens of other EU countries should have the right to live and work in Britain; today, the same proportion think the opposite.

The rise of Euroscepticism among the electorate is underlined by the surge in Ukip support to 19 per cent, the party's highest showing. The findings appear to give some endorsement to Mr Cameron's attempts to renegotiate the UK's relationship with the EU, as he heads for a showdown with fellow leaders. Last week, the German Chancellor, Angela Merkel, declared that talks on whether Brussels should "give something back" to member states could begin within weeks, suggesting Mr Cameron would have to confront a renegotiation of EU powers in this parliament.

The Dutch Deputy Prime Minister has added his voice to concerns over the "negative consequences of the free movement of workers within the European Union". Writing in The IoS today, Lodewijk Asscher warns: "We need to watch out: in some places the dykes are in danger of bursting.

"Most of us benefit from the free movement of workers within the EU. We do not want to see this pillar damaged through dwindling popular support. That is why we, especially on the European centre-left, must think harder about how to make it work in the interests of all our citizens, not just well-educated professionals."

The ComRes survey also showed some support for Mr Miliband's stance on immigration, as three-quarters of those polled said he was right to admit that the last Labour government made major mistakes on immigration.

The headline figures on voting intentions show Labour's support up to 37 per cent, stretching the party's lead over the Tories by one point since last month. After a brief rally in a handful of polls over the last few weeks, both the Conservatives and the Liberal Democrats have slipped back to the share they registered last month, at 28 per cent and 8 per cent respectively.

Labour maintains its healthy lead despite Mr Miliband's net personal ratings plummeting 17 points, with only one in five Britons – and fewer than half of Labour voters – now saying he is turning out to be a good leader of the Labour Party.

Mr Cameron's rating also fell slightly, with three in 10 people saying he is turning out to be a good Prime Minister, but more than half saying he is not.

The poll confirms the Prime Minister's problem with people who voted Tory in 2010, who make up more than one in four of those who give him a negative rating, compared with only 9 per cent of current Conservative voters.

As in previous polls, Ukip voters are particularly critical of Mr Cameron, with almost three-quarters giving him a negative rating – which is nearly as bad as the Prime Minister's showing among Labour voters.

ComRes interviewed 2,001 British adults online between 14 and 15 August 2013. Data were weighted to be demographically representative of all British adults. Data were also weighted by past vote recall.