A directive from Brussels that gives consumers the right to cancel orders made over the internet comes into force this week. But legal experts have questioned how effective the ruling will be.

Under the European Commission's Distance Selling Directive, shoppers buying goods or services online will be given an automatic right to cancel an order and claim a refund of any money paid - even after goods are dispatched. Unless agreed beforehand, consumers can also claim a refund for goods that are not dispatched within 30 days.

The directive applies to all contracts not conducted face-to-face. As such, this includes orders made by phone, fax or mail - not just those made over the internet.

However, there are exceptions, including business-to-business contracts, time-sensitive items such as airline tickets, and goods for everyday use such as food or drink. Financial service contracts, for example insurance, are also outside the scope of the directive.

Dai Davis, head of the IT group at law firm Nabarro Nathanson, said the regulation would give extra protection to consumers and establish a "cooling off" period for ecommerce similar to what already exists for credit finance, but he is sceptical about how effective the ruling may be.

"The directive protects people to a certain extent, but there is no requirement for US vendors to obey it," he said.

Davis added that consumers tend to buy from the cheapest website rather than the nearest, and that many may not want to wait seven days to receive goods.

"If people have to wait a week to get things sent to them within Europe it'd be quicker to get it air mailed from America," said Davis, who added that it is the location of the consumer that determines whether the legislation applies.

The UK government is required to implement the directive by 4 June, but this deadline will not be met because officials have entered into further consultation.

A spokesman for the Department of Trade and Industry said that rapid advances in technology had prompted the government to look again at the draft regulations it would enact to meet the directive's requirements. He said the government hopes to put regulations in place by July.

When the directive comes into force in European Union countries, suppliers involved in distance selling will be required to notify customers of their right to withdraw from a contract and provide shoppers with a suitable cancellation form.