The principle of free trade is one of the main pillars on which the economic integration of the EU rests.

This legal principle is contained in art 30 of the EC Treaty, which prohibits quantitative restrictions and measures of equivalent effect.

It has become one of the key factors in creating the EU's economic area, in which market forces are free to operate without national boundaries.

In contrast with its striking brevity, interpretation of art 30 has given it a very large scope of application.

This is due to the European Court's sweeping definition of measures of equivalent effect in Procureur du Roi v Dassonville [1974] 2 CMLR 436.

This definition looks not only to discrimination, even indirect, but also to the effect on trade within the EU, and not just to actual hindrance, but even to potential indirect hindrance, regardless of the purpose of the measure.Although in keeping with the aims of free trade and market integration, such broad based definition restricts the scope for member states to regulate their economic life according to their divergent cultural and social characteristics.

Member states are allowed to regulate free trade only on the grounds enumerated, exhaustively it seems , in art 36 EC.

However, the European Court of Justice in the Cassis de Dijon case (Rewe-Zentrale AG v Bundes-monopolverwaltung f-r Brantwein [1979] 3 CMLR 494) distinguished its position in relation to indistinctly applicable measures, ie measures that apply to domestic and imported products alike whilst imposing greater burdens on imports.

In this case, the court stated that the indistinctly applicable measure is justifiable if it 'is necessary in order to satisfy mandatory requirements relating to the effectiveness of fiscal supervision, the protection of public health, the fairness of commercial transactions and the defence of the consumer'.In subsequent cases, the court added to the ever expanding list of mandatory requirements, the protection of the environment (Commission v Denmark (re disposable beer cans) [1989] 1 CMLR 619), the protection of culture (Cin-th-que SA v Federation Nationale des Cinemas Fran-aises [1986] 1 CMLR 365), and measures designed to protect 'national or regional socio-cultural characteristics' (Torfaen Borough Council v B & Q plc [1990] 1 CMLR 235).Decisions of the court have not always been clear as to the scope of art 30, as was stated in the High Court in South Pembrokeshire District Council v Wendy Fair Markets Ltd [1993] 1 CMLR 213.

The defendant had claimed that an ancient 14th century monopoly right to hold a market in the small Welsh town infringed art 30.

This sentiment is echoed by many distinguished legal writers who are campaigning for the re-examination and clarification of the court's case law on the application of art 30.

The court's judgments are often unclear and inconsistent, to the point that it has become very difficult for legal practitioners to advise their clients with any degree of certainty.The Court of Justice declared in its 24 November 1993 judgment in B Keck and D Mithouard, cases C/267 and 268/191, that in the light of criticism and confusion, and 'in view of the increasing tendency of traders to invoke art 30 of the Treaty as a means of challenging any rules whose effect is to limit their commercial freedom, even where such rules are not aimed at products from other member states, the court considers it necessary to re-examine and clarify the case law on this matter'.The case concerned criminal prosecutions being brought against the defendants alleging reselling unaltered products at prices lower than the actual purchase price (resale at a loss), this form of marketing being prohibited by French law.

In their defence, the defendants contended inter alia that the prohibition on resale at a loss is contrary to art 30.

The court held that 'contrary to previous judgments, a national provision which restricts or prohibits certain selling arrangements is not such as to hinder directly or indirectly, actually or potentially, trade between member states within the meaning of the Dassonville judgment, provided that those provisions apply to all affected traders operating within the national territory and provided that they affect in the same manner, in law and in fact, the marketing of domestic products and of those from other member states'.Accordingly, art 30 did not apply to the French prohibition on 'resale at loss'.

The measure itself was not such as to hinder trade between member states within the meaning of Dassonville.

The court therefore reaffirmed Dassonville, but nuanced its scope.

The Dassonville formula applies to any measure 'which is capable of directly or indirectly, actually or potentially, hindering intra-community trade'.

The judgment, however, states that although the purpose of the measure was not to regulate trade between member states, it might have a restrictive effect on sales and hence the volume of imports from other member states.

In Keck, French law prevented a potential importer from introducing a new product on the market using an accepted method of sales promotion.

Therefore, the fact that the national rule is capable of affecting the trade between member states is not sufficient to bring it within the ambit of art 30.The court also reaffirmed the Cassis de Dijon principle of equivalence and the rule of reason; that is, national measures which prevent goods that have been lawfully produced and marketed in one member state from being lawfully marketed in another member state fall within art 30, unless the purpose of the measure fulfils a 'mandatory requirement' and its effect is proportionate to the purpose.

The court clearly stated that prohibitions which are caught by art 30 are requirements such as form, size, weight, composition, presentation, labelling and packaging.It was equally important that the provision of the legislation in question did not intend to regulate trade in goods between member states and the fulfilment of the legislative requirements should not prevent access of the good to the market or to impede access any more that it prevents the access of domestic products.

The court seemed to refer to national equal burden rules, which fall outside the scope of art 30.

Already, in the Sunday trading case of Torfaen, the court concluded that where a rule imposes an equal burden on imports and domestic goods it is outside the scope of art 30, provided it pursues the public interest that overrides the principle of free movement of goods and that it is proportionate to that end.

The judgment in that case brought equal-burden rules largely into line with those taken in respect of dual-burden rules, as in Cassis de Dijon.

However, there is a substantial difference: the rule in Torfaen restricted the trade simply because it existed, not because it was different from the rule in the state of origin of the goods.

The Cassis-type rules have a protective effect; Sunday trading rules have not and are an equal-burden rule.The effect of Keck must be that the equal-burden rules fall outside of art 30 and are no longer subject to justification by mandatory requirements and rules of proportionality.

The Court of Justice seems to have shifted its position from that taken in Sunday trading cases and put equal-burden selling arrangements beyond the reach of EU law.

This decision therefore takes outside of the scope of art 30 the Sunday trading cases, notably Torfaen, Stoke City Council and Norwich City Council v B&Q plc [1993] 1 CMLR 426.

The Sunday trading case of Wellingborough Council v Payless [1990] 1 CMLR 773 fell outside the scope of art 30 because it did not affect interstate trade and it therefore stayed within national jurisdiction.

The same reasoning was offered in Quenntlynn v Southend Borough Council [1990] 3 CMLR 55 and Sheptonhurst v Newham Borough Council [1991] 3 CMLR 463: in the first case in relation to prohibition on the sale of lawful sex articles on unlicensed premises, and in the second the local council's refusal to issue a sex shop licence.The court acknowledged that some previously decided cases are no longer valid but omitted to state which.

What, then, has Keck overruled? The court may have been referring to equal-burden rule cases, such as Sunday trading cases.

These cases therefore no longer represent good law.

However in V erband Socialer Wettbewert eV v Clinique Laboratoires SNC, case C-315/92, 2 February 1994, the court referred to Buet [1989] ECR 1235, which concerned door-to-door selling, as an example of the consistent application of the proportionality rule in relation to the rule of reason and art 36.

This would seem to indicate that judgments which deal with non-discriminatory rules that prevent market penetration are still of value.The Advocate-General Van Gerven considered that Blesgen [1983] 1 CMLR 431, which concerned the prohibition of stocking and selling for consumption on the premises spirits stronger than permitted under Belgian law, is a case similar to Keck.

However, the court decided that in Blesgen interstate trade was not affected and it therefore escaped the prohibition contained in art 30 on that account.

This reasoning could easily have been used in Keck, since the products concerned were not imported from other member states.

L Gormley, in 'Reasoning renounced? The remarkable judgment in Keck and Mithouard', European Business Law Review, March 1994, feels that the 'Keck and Mithouard judgment is broadly enough stated to justify an assertion that the Oosthoek ([1993] 3 CMLR 428) line of cases concerning selling arrangements, ie offering of free gifts with encyclopaedias, is no longer a good law'.The judgment in Keck has been followed in Hunermund v Landesapothekerkammer Baden-Wurttenberg, case C-292/92, 15 December 1993.

This concerned the compatibility with art 30 of professional rules of Baden-Wurttenberg Lander's Chamber of Pharmacists, which prohibited the pharmacists practising in the Lander from advertising para-pharmaceutical products which they were allowed to offer for sale.

The court observed that the rule in question was not concerned with trade in goods between member states.

It considered that such a rule was likely to restrict the volume of sales and, consequently, the volume of sales of para-pharmaceutical products from other member states, in so far as deprived the pharmacists concerned of sales promotion for such products.

Provided that the rule applied to all traders concerned in that national territory and provided that they are affected in the same way, in law and in practice, the marketing of domestic products and those from other member states, the application from other member states of domestic provisions restricting or prohibiting certain methods of sale was not likely to impede directly or indirectly, actually or potentially, trade between member states.The court concluded that regulations at issue, which applied without distinction according to the origin of the products in question to all pharmacists covered by the professional chamber, did not affect the marketing or products from other member states differently from that of domestic products, therefore art 30 did not apply to the prohibition on advertising.In further cases that followed, Tanstation 't Heukske vof and JBE Boermans (case C-401/9 and case C-402/92 of ECJ, 2 June 1994) relating to the requirement of the Netherlands rules concerning the closing of petrol stations, and Punto Casa SpA v Sindaco del Commune di Capena (case C-69/93 and C-258/93 judgment of ECJ, 2 June 1994) relating to the Italian legislation on the closure of retail outlets on Sunday, the Court of Justice repeated the reasoning in Keck and Hunermund and has taken out of the ambit of art 30 EC national rules that regulate the times and places at which the goods may be sold to consumers.It would seem that the court is taking the rules concerning selling arrang ements out of the scope of the basic principle in Dassonville and seems to have taken a policy decision that it will leave the national non-discriminatory regulation of socio-economic life to national authorities.

This is in keeping with the legal and political principle of subsidiarity.Keck did restrict the scope of art 30 but further litigation will be necessary to establish how great this restriction is.

Measures which are not protectionist in nature and are not imposing selling restrictions on importers which are different from those imposed on domestic traders are arguably not of equivalent effect to actual restrictions on imports.

Perhaps this is an indication that the court will in future confine art 30 to the areas genuinely capable of impeding the establishment of the common market