Diageo's successful "Baileys minis" series of single measure drinks can remain on sale in continental Europe following a ruling yesterday by Europe's highest court.

The European Court of Justice (ECJ) dismissed an argument by a German drinks association, which was supported by the French and Belgian governments, that the small measurements used by Diageo for the Baileys minis series contravened EU law.

The case is the latest instalment in a long-running battle over the imperial units of measurement used in the Republic and the UK and the metric measurements commonly used in continental Europe.

On the continent the standard spirit measurements are 0.05 litres and 0.1 litres. But Baileys minis are sold in 0.071 litre bottles, which in imperial measure is half a gill - the traditional unit of measurement in the Irish drinks industry. However, German spirits industry association Schutzverband der Spirituosen-Industrie took a case in the German courts arguing that this measurement ran counter to an EU regulation dating from 1974. It wanted to ban the import and marketing of Baileys minis. The German court referred the legal question to the ECJ for its interpretation of European law regarding units of measurement.

In its ruling yesterday the ECJ found that "pre-packages with a nominal volume of 0.071 litres" which are "lawfully manufactured and marketed" in the Republic or the UK may also be sold in other EU countries.

The court concluded that to prohibit the sale of goods in volumes of 0.071 litres that are lawfully marketed in the Republic and the UK would be contrary to the free movement of goods, a core principle within the 27 member EU.

The court also noted that other EU directives require that the volume of liquid must be clearly marked on the packaging, ensuring that consumers in continental Europe would be properly informed of the precise volume.

Diageo has been selling its miniature bottles of Baileys' liquor in Germany since 2004. It uses the same size in France, the Netherlands, Belgium and Greece and has experienced considerable success with the marketing initiative.

The court's finding in favour of Diageo reflects a trend in Europe towards compromise on the thorny issue of different units of measurement. After a 10-year fight with the Republic and the UK over converting to metric measurements, last month the European Commission finally granted a derogation to the states to enable them to continue using specific imperial standards such as "the pint" indefinitely.