Darwen's academy plans have been boosted by the news that students of such centres improve three times faster than mainstream pupils.

But critics like the National Union of Teachers say the figures simply prove that academies are selective.

Darwen's academy will replace Darwen Moorland High School in September 2008, based at what is currently Redearth Road.

By having businesses at the helm, academies aim to raise standards by offering increased resources and expert skills from the world of work.

The £35million Darwen project involves knocking down 150 homes to create space for a 1,600-place school which will include a sixth form centre.

Figures released today by the Department of Education and Skills show the number of 15-year-olds achieving five A to C grade GCSEs across the UK's 27 academies has gone up eight per cent in the last 12 months from 28.4 to 36.4 per cent.

But in mainstream education, pupils have only improved by 2.6 per cent in the past year, with grades rising from 53.7 to 56.3 per cent.

And although the A to C rate at academies is nearly 20 per cent lower than the national average, the government insists the gradual improvements at academies show they are working.

Blackburn with Darwen Council's executive member for education, Dave Hollings, took heart from the statistics.

He said: "It is very pleasing there is evidence that academies can improve performance for children but we will not be complacent.

"Just opening up a school and calling it an academy is no guarantee it will work so we will work hard and make sure we are able to improve the outcomes of pupils at the Darwen academy."

But Simon Jones, NUT executive member of the NUT Lancashire and secretary of Blackburn and Darwen branch, said the figures rubber- stamped the union's belief that academies raised standards through a selective approach.

He added: "It may be that these figures are accurate but we have to look at why the results are increasing.

"Are the academies being more selective about the pupils they admit? We have had assurances that the Darwen academy won't be selective but many of them are.

"If you select the better pupils in the first place, surely the results should be better.

"If any school hand- picked its pupils this would be the case, but the less-academic pupils still have to be able to get an education. This is one of the reasons we continue to oppose the academy in Darwen."