In 1988, the urban designer Francis Tibbalds was commissioned by the city council to write a policy document which was called the Birmingham Urban Design Study (BUDS).

Published in 1990, this was described at the time as the best piece of urban design policy produced by a British city.

One of BUDS' policies was about the placing of tall buildings. Tibbalds identified a physical fact that should have been obvious but which had been obscured by decades of highway engineering and indiscriminate building: that Birmingham city centre is on top of a hill. Or more exactly, a ridge, that runs southwest to northeast.

He advocated that the heights of new buildings should be related to where they were placed on the contours. Tall buildings should go on the ridge, and as you got lower down the slope, building heights should also be lower. The pattern of buildings should match the shape of the land.

This policy became more detailed in 2003 in a planning document called High Places. It specifies a central ridge zone, stretching from Five Ways to the University of Aston, within which tall buildings are allowed and encouraged. Explicitly excluded outside this zone are tall buildings in conservation areas or next to listed buildings.

However, as with other good planning policies, the planning committee and its officers often choose to ignore it when it's convenient to do so. A recent example is the Beorma development next to the Bullring, where a 30-storey tower, approved last month, will be built at the corner of Digbeth and Park Street.

It is outside the central ridge zone – in fact nearer to the River Rea than to the top of the ridge: it is in the Digbeth and Deritend Conservation Area, whose management plan specifically prohibits tall buildings: and it is a few metres away from the Grade II* listed St Martin's Church.

Why do we bother to have policies?

The 30-storey will replace this derelict site opposite Selfridges
The 30-storey will replace this derelict site opposite Selfridges

I am sometimes accused of being opposed to tall buildings. I am not – no more than I am opposed to low buildings, or pointy buildings, or pink buildings. All of these can be appropriate, if in the right place and well designed.

But tall buildings are a special case, just because they are so visible. They have a special responsibility to be correctly sited and architecturally interesting because you can't avoid seeing them.

A tall building is rather like someone talking loudly at a party. If they have something entertaining to say it can be quite fun: if they are boring or offensive it can be deadly.

The Rotunda is a good example of a successful tall building. It is prominently sited on the edge of the ridge escarpment, making it a landmark and both before and after its remodelling by Glenn Howells Architects, it is a unique and distinctive piece of architecture.

The Beorma tower has had a long and complicated history.

The Kuwaiti developer, Salhia Investments, initially commissioned the London architect Trevor Horne to design the whole development. Horne won planning approval for a 27-storey office tower, in 2009.

Horne's design idea for the tower was interesting, though possibly a bit wacky. The tower was to be made up of narrow slivers articulated together, which were meant to reflect the medieval land subdivision known as burgage plots.

Although most of the buildings on this side of Digbeth are from the 19th century, the pattern of narrow building plots has largely survived from that which was laid down in the 12th century.

We are familiar with the kind of street which is made up of buildings on medieval burgage plots. In Digbeth just a fragment survives, but cities like York, Winchester and Norwich are largely composed of them.

CGI of phases two and three of the Beorma Quarter
CGI of phases two and three of the Beorma Quarter

They generate an urban scale which is almost invariably attractive and appealing: often called a human scale. Whether that same scale can be generated in a 27-storey building is another matter. I doubt it can.

But the resultant articulation was undeniably unusual and interesting and, combined with a jagged skyline, resulted in a distinctive design. At some point last year, Salhia replaced Horne with the multi-national firm Broadway Malyan, which has a Birmingham office.

I don't know why: they apparently instructed Broadway Malyan not to talk to me, which seems an odd decision when someone wants to write about your development.

It often happens that a developer switches from an individualistic architect who wins planning approval, to a more commercial architect to then deliver the building – sometimes called the executive architect.

There is often a dumbing-down of the design. To their credit, architects at Broadway Malyan have retained Horne's burgage plot idea. They have simplified it: it is less spectacular, but still more distinctive than most high-rises. It is also now contains both offices and apartments and an extra three storeys.

It will have a lot of sandstone, reflecting the local geology and relating to St Martin's opposite. The sandstone will form vertical ribs, defining the burgage plot divisions, framing areas of glass and metal.

Even though downhill from the ridge, its distinctive profile will be seen from a long distance but, as with many tall buildings, particularly critical to its success is how it will work at street level.

Salhia has got a particularly difficult location, on the hostile and dangerous street junction next to St Martin's Church.

It faces the urban design disaster which is Selfridges, with its blank, lifeless façade along Park Street (another result of a good policy being ignored), and directly opposite the entrance and exit of the Bullring basement car park.

In urban design terms, one responsibility of Hammerson's Bullring development was to enable the economic regeneration which it represented to then cross over Park Street into Digbeth. But Selfridges' blankness, and the traffic which is generated by the ill-advised car park, has made it difficult for this to happen.

I wish the Beorma development well, despite its breach of policy, and hope it can generate a busy, active and sociable street edge. But it is starting from a difficult place.

Joe Holyoak is an architect, lecturer and urban designer