As the situation in the high street goes from bad to worse, can anything be done to stop the slides in footfall, sales and profits? Step forward Mary Portas and her menu of 28 ideas. Is there anything among them that would bring short-term relief to retailers on the brink?

Afraid not. Some Town Teams could be set up relatively quickly, especially given the cash incentives available, but it will probably take quite a time for them to do something useful. Local authorities could in theory establish free controlled parking areas, but would have to find the lost revenue elsewhere. In any event, free parking alone would do little to save the high street.

The remaining 26 proposals either require changes in regulations or rely on some process of consultation with one or more interested parties.

Another weakness in the review is its limited evidential base. The recommendations appear to have been culled from a series of site visits, written submissions and conversations with an assortment of savants, local authorities and retailers, while several multiples with a big stake in town centres were ignored.

Much of this input was no doubt relevant and well-intentioned. Yet here and there we encounter a bald, unsupported assertion - for example, that “the most sustainable form of retail development is in town centres”.

Ms Portas also dislikes betting shops and charity outlets, despite the fact that they generate a significant footfall. And occasionally we encounter something really daft, like her claim that planning needs to be “a much more collaborative process than at present” - a certain recipe for slowing any action down to geological speed.

A good background paper from BIS officials implicitly challenged many conventional utterances about the decline of the high street. It suggested four key performance indicators that could usefully measure the health of a given town centre - customer footfall, consumer and business satisfaction, diversity and economic activity. In short, we need to know far more about what makes our high streets tick before we can devise effective strategies for their renaissance.

So, no quick fixes and a lot of spadework still to do.