Ed Miliband will target the youth vote as he accuses the Conservatives and Liberal Democrats of denying thousands of students a ballot paper.

Mr Miliband will make the charge in Nick Clegg's Sheffield constituency, where Labour hopes to unseat the Lib Dem leader as part of a so-called "decapitation" strategy.

The university town is home to many young voters who backed the Lib Dems at the last election but feel let down by its tuition fees U-turn.

In his speech Mr Miliband will accuse the Coalition government of "betraying" young people and "short changing" their futures.

He will say: "There is nothing more pressing at this election than the future of young people.... and the outcome of this election will determine what kind of future young people have."

He will call on politicians, universities and council to address their concerns with action on low pay, affordable housing, jobs, skills and climate change.

But he will also warn that almost one million people have fallen off the Electoral Register, including hundreds of thousands of young people, because of Coalition reforms.

The problem is understood to be less acute in Scotland where many registered in large numbers before the independence referendum.

However, even in the run up to that poll experts warned that students, who often live far from home, risked missing out by not being on the electoral roll.

Labour plans to publish a specific youth manifesto ahead of May's general election.

All the political parties have faced criticism for appearing to offer sweeteners to the so-called "grey vote", older people who are more likely to use their ballot papers than younger people.

But think tank Demos has warned up to three million 16 to 25-year-olds have yet to decide how to vote - and could decide who wins in May.

Mr Miliband has warned that trust in politicians in general was damaged when Nick Clegg broke his pledge not to increase tuition fees.

The Labour leader has also promised to "lead from front" on international efforts to combat climate change, as part of a pre-election push to appeal to would-be Green voters.

Labour are concerned that the pro-environmental party is attracting a lot of support from former Lib Dem voters.

Polls suggest that many Lib Dems MPs will lose their jobs in May.

So close are the polls that experts suggest that winning those seats could help secure the keys to Downing Street.

Mr Miliband has also defended his plans for a mansion tax on properties worth more than £2 million.

London Labour MPs protested last week at plans by Scottish Labour leader Jim Murphy to spend some of the money raised on nurses north of the border.