The government is preparing to warn backbench rebels that they must accept university top-up fees or risk losing a large new package of help for poorer students.

Education secretary Charles Clarke has agreed to boost annual maintenance grants from £1,000 to £3,000 for the poorest students.

Ministers are expected to unveil the Higher Education Bill on Wednesday or Thursday.

Appearing on the BBC's Breakfast with Frost yesterday, former Labour chief whip Nick Brown accused the government of creating an "unbearable debt burden" for families.