While UK and EU trade mark law and legislation does allow shape marks to be registered and there are good examples of this - the shape of the Coca Cola bottle is one - it is nonetheless still notoriously difficult to obtain, never mind enforce a registered shape trade mark.

The main difficulty associated with this is that the shape to be registered is usually that of the product. That shape may not be unique to that product and may not be used by a brand as such or serve to indicate the source of the product to consumers.

The latest business to fall at the relevant legal hurdles is the London Taxi Company (LTC).

LTC had successfully managed to register a trade mark over the shape of what some consider to be the 'iconic' London black cab but when it came to enforcing it against a competitor it was told by the Court of Appeal (upholding the decision of the court below) that the shape of the traditional London black cab was not distinctive enough to be a trade mark.

The Appeal judges dismissed the challenge by the taxi company earlier this week, although one of the judges did indicate that it might be worth asking the Supreme Court justices to consider the case.

LTC had taken a passing off and trade mark infringement action against the maker of the new electric Metrocab taxi based on 2 trademarks, depicting 2 different models of black cabs.

The first instance and Appeal Court rejected the passing off claim and found two trademarks to be invalid for class 12 (taxis) because they were "devoid of inherent distinctive character". This was because they considered that the marks would be seen by the average consumer as only a variation to the typical shape of a taxi. In addition they would not be viewed by them as identifying the origin of the goods.

Even if they had been valid the court made it clear that it would have found there was no infringement or passing off in any event.

Whilst it is not easy to successfully obtain, retain and enforce a shape trade mark it is, in principle, possible. If the shape is one recognised by the public as identifying particular goods and services from a particular source, then it should be valid as long as it has been used as a trade mark. In this case the cab shape and features of it (e.g. round headlamps, the slope of the windscreen) were considered not to be sufficiently different to the equivalent ones of a standard car.

A trade mark is an extremely valuable IP right and can give a time unlimited monopoly to its owner over its subject matter. It is therefore understandably desirable that there are strict tests for trade marks to pass, to be kept on the register, so that 3rd parties are not unfairly prevented from using words/signs (or for that matter shapes) which are generic/descriptive/in common use.

It will be interesting to see if this case is taken all the way to the Supreme Court.