The EU has refused to import beef from North America that has been treated with growth hormones, arguing that it could pose a health risk.

But the WTO disputes panel ruled that the EU was in breach of international trade sanctions, and has now allowed the US and Canada to impose $124m in punitive tariffs on EU agricultural products.

The ruling clears the way for the United States to begin imposing the tariffs on 29 July.

The tariffs are designed to hit hardest those countries which have been most vocal in their oppoistion to US beef.

The US has already announced a long list of products, from Roquefort cheese to Danish pork, that will be, in effect, frozen out of US markets.

The UK, which has argued in favour of lifting the ban, has escaped without any tariff damage.

Canada will produce its own list of punitive tariffs on EU goods shortly.

Goods from the European Union's 15 member states, ranging from handbags to bed linen, are already subject to extra U.S. tariffs worth $191m after Washington won WTO approval in April for sanctions in a row over EU banana import rules.

The EU, which had accepted it would have to agree with the WTO findings, had hoped to negotiate with the United States on a settlement under which it would cut tariffs on an agreed range of US imports to the value the arbitrators had set.