By Ian Dunt
Plans to treble tuition fees are actually more progressive than the current system, experts have found.
The finding will be treated as a lifesaver by the government, which is frantically trying to prevent a wide scale rebellion.
All government ministers currently abroad have been ordered to return to the UK for the vote, in a sign that the result of tomorrow's vote may be much closer than planned.
Meanwhile, both sides of the tuition fee debate made last-minute manoeuvres in a bid to consolidate their position.
During PMQs today, Ed Miliband and David Cameron engaged in a bitter war of words over the issue, with the Labour leader accusing the prime minister of being out of touch with the public.
An Institute of Fiscal Studies (IFS) report published today said the government proposals were "more progressive than the current system or that proposed by Lord Browne". The last part of that sentence will please Lib Dems, who are desperate to show that they secured reforms to the plans.
Highest earning graduates would pay more on average than under the current system or that proposed by Lord Browne while lower earning graduates would pay back less.
"Graduates from the poorest 30% of households would pay back less than under Lord Browne's proposed system, but more than under the current system," the report reads.
The Liberal Democrat ministerial team agreed to back the move last night, while Labour's team started to unify in its opposition.
Meanwhile, Tory whips concentrated on keeping their own MPs in line, student activists gathered across the country and the government offered new concessions in a bid to minimise a Commons rebellion tomorrow.
Nick Clegg emerged from a meeting of the Liberal Democrat parliamentary party last night to insist that all his ministerial team would vote for the rise in the fees on Thursday, suggesting that the rebellion against the plan was starting to dissolve.
In a sign of how Mr Clegg won his ministerial team over, the Department of Business, Innovation and Skills (Bis) released details of new concessions today.
These include full loan support for part-time students working at least 25% of the time - as opposed to the 33% originally envisaged.
There will also be an annual uprating of the earnings threshold at which fees need to be repaid in line with earnings from 2016, rather than every five years as originally planned.
The £15,000 earnings threshold that applies in the current student finance system will be uprated annually in line with inflation from 2012, in a move to help existing graduates and try to stem the rising tide of student protests against the policy.
John Denham, Labour's shadow business secretary, commented: "The gvernment's latest attempts to shore up its plans for a massive hike in tuition fees simply show that their plans are not worked out.
"But these desperate measures are not good enough."
Inside last night's meeting, Mr Clegg asked his party to "walk through the fire" with him as the vote approached.
"I've listened to the debate, I've listened to the protesters, I've listened to my party," he said afterwards.
"And I can announce now that all Liberal Democrat ministers - every single one - will vote for this measure when it comes to the vote on Thursday.
"Because in these difficult circumstances, this is the best way to ensure we have world-class universities for generations to come."
But the resolve of ministerial Lib Dems still left the party's MPs unaccounted for. Up to half of them could vote with Labour against the proposals.
Meanwhile, there were rumblings of discontent within the Tory party as well. Many more Conservatives than previously thought are believed to be uncomfortable with the policy and considering abstaining or even voting with the opposition if they feel Ed Miliband is not being overly party political.
Mr Miliband appeared to have consolidated Labour's position ahead of tomorrow's vote, after Alan Johnson made a spectacular U-turn on the subject of a graduate tax.
After coming out in support of the graduate tax during his leadership campaign, Mr Miliband's favoured policy was instantly destabilised by outspoken comments from his shadow chancellor saying he still supported tuition fees, which he originally helped to bring in while in government.
Mr Johnson said he had finally been convinced of the merits of a graduate tax in today's Times.
Labour's priority "this week is to defeat the government," he wrote.
"If we fail, our priority will be to offer the country a fairer alternative for stronger universities and a better deal for our young people."
Mr Johnson said the coalition was "abusing the legacy I left them".
He added: "We are now seeing how casually the variable fees system can be distorted with such damaging effects.
"It is in these circumstances that there is a strong case for a graduate tax, which may offer a fairer way of sharing costs between individuals and government."
Conservative party chairman Baroness Warsi hit back: "For years, Alan Johnson has opposed Ed Miliband's graduate tax as an unfair deal for students - especially for those starting their careers on lower incomes.
"His half-hearted conversion to the policy does little to clear up Labour's dithering over higher education funding."
The debate is expected to go late into the night tomorrow, but it would take around 40 rebels for the government to lose the vote.