THE latest Lib-Con Coalition spat took a new twist last night when Downing Street sources contradicted Nick Clegg and insisted David Cameron had known about the Education Secretary's controversial plans to scrap GCSEs in England.

Earlier, as resentment among LibDems continued to seethe at what they see as Michael Gove's misguided attempt to create a two-tier education system, Mr Clegg declared: "This has not been subject to collective discussion in government. Neither myself nor the Prime Minister were aware of it."

Mr Clegg made clear the Secretary of State stood no chance of making his reform plans government policy without the backing of his LibDem colleagues.

Asked if Mr Gove's proposals would go ahead without his support, Mr Clegg replied: "By definition, in a government, if you have collective agreement, and particularly in a coalition, it requires support from all sides."

A Number 10 spokeswoman said the Prime Minister agreed with Mr Gove that "we do need to look again at the exam system".

Later, Downing Street sources claimed Mr Cameron did know the details but that they had not been submitted for formal government discussion.

The leaked proposals include the most radical shake-up of the exams system south of the Border for 30 years, replacing GCSEs with O-levels in subjects such as English, maths, the humanities and science while less able pupils would take simpler qualifications similar to old-style CSEs.

School leaders have warned the move was a "bombshell" and would write off large swathes of children.