By Stephen Dalziel BBC Russian affairs analyst

"Russian vodka" is often made outside the country's borders

Russia's patent office has ruled that the term "Russian vodka" can be applied only to vodka produced according to established criteria inside Russia itself.

This is in line with international practice protecting such terms as Scotch whisky, Champagne and Parma ham.

"Russia" and "vodka" are linked in people's minds like "horse and cart" or "bread and butter".

But this has led certain producers of the clear, powerful liquid to use the term "Russian vodka" to describe something made a long way from the country's borders.

Parma ham producers recently won a court case to protect their trademark

There is a long legal process to be followed if the Russians want to protect their trademark worldwide.

They will have to file detailed applications to patent offices in every country where they believe the non-genuine article might be produced.

It is likely that their application will be for Russian vodka to be regarded as a geographical appellation.

This is why only the sparkling white wine from the Champagne region of France can be called Champagne.

And it is why the Parma ham producers from the Po valley in Italy recently won a case whereby only the ham produced, cured and sliced in their region can bear the name of Parma ham.

Sometimes there are ways around the regulations.

A village in Japan was re-named Scotland, so that the whisky produced there could be said to be "made in Scotland".