Charles Clarke has accused the Conservatives of being confused about their education policies.

Speaking ahead of a visit to schools in the Midlands with the prime minister, the education secretary warned that the Tories would "take education back to the past".

As election campaigning continued, Clarke said voters "have no idea" how Conservative plans for "pupil passports" will be implemented.

"Tories can't even agree what it is," he said.

"But we should not let Tory confusion hide the real agenda of cuts to take education back to the past."

While the Conservatives have pledged to match Labour's education spending, Clarke said their policies could cost an additional £1 billion.

"Since 1997 this government has increased the number of teachers by 28,000 and support staff by 105,000," added the education secretary.

"A vote for the Tories is a vote to go back to the past."