By Alan Clawley.

When the news broke that John Lewis was planning to build a new department store on top of New Street Gateway it was accompanied by the usual computer-generated graphic. The multi-story shop appeared like a pure white space-craft that had landed on top of the undulating stainless steel façade of the new concourse amid a cloud of white gas which conveniently hid any awkward design issues.

I was curious to know how the new store was going to be integrated into the existing designs so I went to have a look at the architects’ model of the Gateway in the Mailbox.

The two selling points of the Gateway are a big skylight that will let natural light flood into the concourse and a shiny façade made of stainless steel, obviously inspired by Frank Gehry’s recent work.

Both of these features may be jeopardized by the John Lewis project.

We don’t know how big the store will be, but it would need to have a pretty small ‘footprint’ if it is to avoid building over the proposed skylight. Even then it would almost certainly steal daylight from it.

We still don’t know how the store will relate to the public concourse. If it occupies a large part of the concourse it is bound to squeeze out many smaller units. If it doesn’t it will lose the commercial benefit of having a ground floor.

There are bound to be many structural and planning issues to resolve before we can see how it will work.

The Gateway façade is merely a skin that is supported by a steel skeleton, in the same manner as Selfridges. I often pass the mock-up next to Small Heath Bridge and can see how complex the frame of girders will have to be to support the bent rectangular sheets of stainless steel that form the skin. This will no doubt be eye-catching. In fact its concave surface could (and does) behave like a mirror that focuses the suns rays on other buildings and can blind whoever is in the wrong spot.

It is difficult to see then, how an irregular, structurally complex feature can visually and structurally support a regular multi-storey structure like a department store without seriously undermining the entire Gateway design concept.

In the meantime, Councillor Whitby continues to bask in the glory of matching up a prestigious retailer with his much-trumpeted New Street Gateway project. But he doesn’t have to make it work.