CHANGES to the design of Oxford’s new £35m science discovery centre have not gone far enough, according to campaigners.

The height of the Magnet building was reduced by two metres and gaps included in the building to allow views of the Castle Mound, following concerns raised at an initial consultation.

But heritage groups say it would still block views of Castle Mound, one of Oxford’s most historic sites.

The proposed visitor attraction has been designed by one of the world’s leading architects to showcase science and technological expertise in Oxfordshire.

The Magnet is expected to attract 150,000 visitors a year, generate income of more than £128m over a decade and create a 100 skilled jobs.

But objections have been raised by English Heritage, Oxford Civic Society and Oxfordshire Architectural and Historical Society, while Oxfordshire County Council, which sold the site for £3.5m, says the centre is “too dominant”.

The opposition is being led by Oxford Preservation Trust (OPT), which oversaw the transformation of the castle site, once home to a Victorian prison, into a successful heritage centre.

Science Oxford, the charity behind the scheme, wants to create in New Road the UK’s first Discovery and Innovation Centre, with a world-class planetarium. It would also be home to 50 local high-tech companies.

Plans were submitted to Oxford City Council in April.

The architects Foster and Partners previous work includes the German Reichstag.

But OPT director Debbie Dance has warned the city council that the Magnet would bring “a profound change to the setting of the Mound and will cause significant harm to it”.

Existing views from Park End Street and Hythe Bridge would be replaced with “glimpses of the Castle Mound through the development,” she said.

And she added: “The Mound is just too important for such treatment. We also express concern over the size and massing of the development, which seems to be using every available space for building upon.”

While the Trust supports the concept of the Magnet, she said: “Oxford Castle is the town’s most significant piece of history outside the university.

“We are disappointed that no attempt has been made to integrate the site with the Castle.”

Peter Thompson, Oxford Civic Society chairman, said: “The proposed development presents only bland, visually heavy facades to the streets adjacent to and enclosing it. These buildings would completely obscure the Castle Mound from view.”

The centre would result in the demolition of Macclesfield House, the 1960s office block, and the Register Office Building on the corner of Tidmarsh Lane and New Road, which Oxfordshire Architectural and Historical Society unsuccessfully tried to have listed.

Paul Brankin, chairman of Science Oxford, said: “We are delighted that the bulk of people who have commented have supported what we are trying to do, which is to put a new kind of centre for science in the middle of Oxford.

“We have done a lot of work and we want to build something that the people of Oxford like and will come to.”

He said that Science Oxford would now meet with groups in the hope of reaching agreement on designs, which were first changed following a consultation in 2010.