The prime minister is to mount a vigorous defence of the government's plan to allow English universities to charge up to �3,000 a year for some courses.

In a speech on Thursday to Labour Party supporters in London, Mr Blair will defend the proposals, allowing increased top-up fees from 2006.

He will argue the reforms are part of a "road to social justice", saying the reform process needs to go "further and faster" across the whole of the public sector.

Blair is set to back the higher education white paper

His comments are unlikely to convince critics within a party already divided over the prospects of war with Iraq.

One of party's biggest backbench rebellions is expected when the higher education proposals reach the Commons.

Under the government's plans, universities will be able to charge different fees up to �3,000.

Students will not have to pay until they graduate, and begin to earn at least �15,000.

The plans are part of a wide-ranging and long-awaited shake-up of higher education in England.

However, students and academics warn the plans could lead to a "two-tier" system and could saddle students with increased debt.

They fear the re-introduction of maintenance grants for the poorest students, and the creation of an "access regulator" will not be enough.

Higher Education Review

Higher limit for tuition fees, up to �3,000 Universities set own fees Scrapping of up-front fees Re-payment after graduation 'Access regulator' to ensure wider intake Return of maintenance grants

Average debts over the course of a three year degree could reach �15,000.

The Tories education secretary, Damian Green, said rows within the Cabinet had led to "messy, botched" proposals which would satisfy no one.

The Liberal Democrats' education spokesman Phil Willis has also expressed his fear the changes will "split" students according to their ability to pay.

The increase in fees is intended to tackle the budget shortfalls facing many universities and help pay for the expansion the government wants.

But 180 Labour and opposition backbenchers have already signed a Commons motion against top-up fees.