Tory plans for a £30 million technical school in Bristol where teenagers can learn vocational skills have had a mixed reception.

The idea, announced by the Conservatives at their conference in Manchester this week, is said by its supporters to be just what Britain's businesses need.

But opponents are concerned about the potential impact on existing schools and colleges.

The Tories said they wanted to see 12 technical schools in major cities including Bristol within five years. These would sponsored by businesses and universities and funded out of the £4 billion academies budget.

Schools in Bristol are due to launch their first three diplomas – qualifications that combine practical and academic learning - next September in engineering, hair and beauty, and construction and the built environment. Marius Frank, head teacher of Bedminster Down School, who is leading the introduction of diplomas in Bristol, said he was pleased that the Tories were endorsing vocational education but warned that politicians should look beyond a "dash for headlines" when setting education policy.

He said: "In my role as Diploma Champion for Bristol, I have seen the power and virtue of collaboration between schools and academies, and how positive and enthusiastic partnership working can make best use of specialist facilities across a city.

"Building new schools is not necessarily the answer: making best use of what we have, with a curriculum that values academic and vocational achievement."

Bristol's schools are already working with each other and with further education colleges to deliver vocational BTEC qualifications for 14-19 year-olds and City of Bristol College is due to open a £30 million South Bristol Skills Academy in Hengrove next September.

Councillor Clare Campion-Smith, cabinet member for children on Lib-Dem-controlled Bristol City Council, said the proposed technical school was an interesting idea

She added: "In the meantime we are working to drive up standards in maths and sciences for all our students, not just those who might attend a new technical school."

Teaching unions were critical of the proposal, saying it showed a "sheep and goats" mentality and risked marginalising youngsters who wanted to follow a vocational route.