ED Miliband has promised "clear, credible and concrete" reforms on immigration, placing them at the heart of a Labour government's programme in a new Immigration Bill to be published if they win victory at the 2015 General Election.

The party leader made the pledge as he visited the Rochester by-election campaign in Kent, which, according to local polls, looks set to return the Tory defector Mark Reckless as Ukip's second MP after its victory in Clacton; Labour is currently trailing in third behind the Conservatives.

Labour MPs had warned of a narrow escape earlier this month in the Manchester seat of Heywood and Middleton. Labour retained the seat in the face of the Ukip threat by just 617 votes, which should be a wake-up call for Mr Miliband, who has been accused of a failure to appreciate the anti-EU party's growing threat to Labour in northern England.

Mr Miliband's election promise came as David Cameron, who has been toughening Tory policy in the face of the threat from Nigel Farage's party, insisted the Conservatives would not echo Ukip's "tone" on immigration, stressing how the British public "want us to continue to be a successful multi-racial country that celebrates the diversity that we have here in the United Kingdom but, at the same time, they want to see fair and controlled immigration."

Under the Miliband plan:

l All public-facing state employees would be required to have a basic standard of English;

l Recruitment agencies would be banned from hiring staff only from abroad;

l Companies employing people from outwith the EU would have to create a local apprenticeship;

l Banning the hiring of foreign workers to undercut UK wages and

l Reintroducing "counting in and counting out" at borders.

These proposals come on top of the party leader's previous hardened commitments to seek longer transitional controls for new member states, stop child benefits being paid to children who live abroad, double the length of time migrants are in Britain before they would be entitled to welfare and introduce stronger rules to deal with foreign criminals.

Noting how the Prime Minister had failed to lower EU migration to Britain, the Labour leader said: "I will not make promises I cannot keep. I will never propose a policy or a course of action that would damage our country."