Whitehall education targets have contributed to youth alienation and "the rise of gun and drug culture", the Liberal Democrats have said.

During Commons education questions on Thursday, Phil Willis pointed to government red tape rather than rap music as a cause of school ill-discipline and a factor in gang culture.

Earlier this week, culture minister Kim Howells had suggested that street music fuelled gun crime.

But Willis asked schools minister Ivan Lewis whether there were other causes for worsening crime statistics.

"Could the minister say what he feels has contributed more to the disillusionment of our young people, indiscipline in our schools, the rise of gun and drug culture? he asked.

"Is it the rap music, or is it in fact the government's obsession with targets, testing and league tables?"

And attacking Labour's record on school exclusions, the Harrogate MP demanded that Lewis cite one performance indicator that had benefited inner city, ethnic minority or special needs children.

"Can the minister point to one single government target that has improved the lot of black ethnic minority students who are more likely to be excluded from school, our [special education needs] students who are seven times more likely to be excluded from schools, and those youngsters in our inner cities who are failing in greater numbers under this government than under the deplorable government that preceded them?"

Lewis accused Willis of doing "an injustice to this extremely complex issue".

The minister spelt out the government's multi-faceted approach to behaviour problems in schools.

"We need a combination of measures which are supporting teachers, enforcing parental responsibility and ensuring that we offer a curriculum that inspires and energise our young people," he told the Commons.

And the Bury South MP backed his government colleague's argument that rap music should take some of the blame.

"But its also true to say...that the influences that impact on young people outside school environment, such as rap music, do make a difference to young people's perception of their community society and the society in which they live."

During later Commons exchanges, education minister Stephen Twigg accused the Conservatives of "scaremongering" over teacher shortages.

The shadow education secretary, Damian Green, had called MPs' attention to research showing that red tape was driving one in three teachers out of the classroom and the profession.

It was a conclusion which Twigg disputed.

"It does show that one in three said they will or probably will leave teaching," he said.

"Half of them will be retiring - they are not people leaving teaching because they are disaffected with government policy, they are retiring because of their age."

"It is absurd to create this kind of scaremongering about the situation with recruitment and retention in our schools. Less than six per cent of those teachers in that survey actually intend to leave teaching altogether. That's the reality of it and that is actually a low figure."

Green accused Twigg of giving an "unbelievably complacent" answer.

"Teachers cite three main reasons for being fed up with their job: unnecessary paperwork, initiative overload and a target-driving culture. The three defining failures of Labour education policy," he insisted.

"Unless you admit to teachers that the gentleman in Whitehall does not always know best he will continue to drive teachers out of our schools and by doing so betray pupils and parents."

The minister rejected the complacency charge.

"I am not complacent. My colleagues are not complacent. We recognise there are issues around teacher workload, we recognise that there are questions of bureaucracy, that's why we are addressing them and I would encourage members on all sides of the House to give their support to our proposals," said Twigg.