A senior Liberal Democrat MP who has become the Government's new Advocate for Access to Education said he regretted the coalition's decision to increase tuition fees but said young people now needed to "understand the facts".
The party's deputy leader, Simon Hughes, who abstained in the crunch Commons vote, said he was "sorry" fees had jumped to a maximum of £9,000 as the result of a "compromise" with the Tories.
But, he insisted, higher tuition fees had not put university education out of young people's reach.
Labour's shadow business secretary John Denham dismissed Mr Hughes' appointment as a sop to the Lib Dems to shore up the coalition.
Mr Hughes told the BBC Radio 4's World At One he would be "independent of Government", saying he hoped to be "constructively helpful".
He told the programme: "I am not there in a way to sell it, I am there to make sure people understand the facts.
"I wouldn't vote for it because I believed that with the higher rate that could go, in some cases, up to £9,000 a year, that could put people off applying to university. The problem with the system is the perception rather than the reality."
But he defended his position, having abstained in the Commons vote on tuition fees.
He added: "I am a member of a party that has believed, and still believes, that we should ideally not have tuition fees.
"That's been our view and it remains the Liberal Democrat view. We didn't win the election, we had to negotiate a coalition with the Conservatives.
"Both other parties had actually signed up to tuition fees so it would have been similar if Labour had been the coalition partner.
"Therefore we weren't able to deliver that. I am sorry about that, I regret that but we live in a real world with coalition politics when you have to compromise and the compromise was that there is the system that has now been agreed but there is much more work to be done."
David Cameron and Nick Clegg's appointment was dismissed by Mr Denham. He said: "I am afraid it is a terribly cynical piece of window dressing. It's all about trying to keep the Liberal Democrats propping up the Tory Government. It's nothing about the opportunities for young people in this country."
Mr Hughes described Mr Denham's comment as "party political", adding that he hoped Labour would work with the Government to encourage young people to go to university as the changes to higher education funding were "more progressive".
He added: "I hope I can bring something from a history of engagement with young people, from the time I was a youth worker to university onwards, to understand how we get messages across but above all get young people on our side so they have the best future."
During the six-month term, Mr Hughes will also contribute to work on finding a suitable replacement for the Education Maintenance Allowance - the axing of which he has criticised.
Announcing the unpaid appointment earlier, the Prime Minister and his coalition deputy renewed complaints that the true impact of the near trebling of maximum fees had been "obscured" by the political row over the Lib Dems breaking a pre-election pledge to oppose rises.
It would be a "tragedy for them" if young people from disadvantaged backgrounds were wrongly put off applying for a degree because of that "misinformation", they said in their letter to Mr Hughes.
His role will involve going into schools to canvass the concerns of less-well-off teenagers and devise with them publicity campaigns to persuade as many as possible to consider higher education.
Mr Hughes is seen as a standard bearer for the left of the party but held back from joining outright rebels in the Commons vote, instead very publicly exercising the right set out in the coalition agreement for Lib Dem MPs to abstain on the issue.
Mr Clegg said the Bermondsey and Old Southwark MP was "ideally suited" to the role as a champion of young people from deprived backgrounds.
"I know Simon will be tireless in seeking the best ways to communicate the opportunities open to young people, just as he will be a strong advocate for them to government," Mr Clegg added.
In their letter to Mr Hughes, Mr Cameron and Mr Clegg defended the Government's efforts to boost the chances of deprived youngsters throughout the education system, including the introduction of a "pupil premium".
"In addition to this focus, we are also particularly concerned to ensure that over the coming years we are successful in our objective of increasing the number of young people from disadvantaged backgrounds going on to higher education.
"In the heat of recent debate, some of the elements of the package have been obscured and there is a material risk that young people - particularly those from disadvantaged groups - may be deterred from applying to university (or continuing their studies to gain university-entrance qualifications) as a result of being misled about the financial impacts of the package.
"This particularly applies to those aged 15-16 who will make decisions in the coming months on whether or not to stay on for A-levels. For them to be deterred from entering university as a result of misinformation would be a tragedy for them.
"We would therefore like to invite you to become the Government's Advocate for Access to Education reporting to us both and with a close engagement with the Social Mobility Inter-Ministerial Group.
"We would like you to take forward an urgent piece of work with young people in secondary education to engage them in how to deliver the Government's objective of increasing educational participation, particularly for those from the most disadvantaged backgrounds."
In the detailed terms of reference, they said the job was to "break down some of the barriers to constructive and rational debate about further and higher education".
That would include detailed consultation with pupils, parents and teachers about the issues and reporting back by the end of January with proposals on how to engage teenagers and inform them of the help available.