An increase in internet connections fuelled by a strong growth in broadband subscriptions has led many companies to step up their marketing investment in the online medium.

However, law firm Eversheds is warning there could be some pitfalls for online advertisers in the West Midlands.

According to figures recently released by the Interactive Advertising Bureau, online advertising expenditure overtook commercial radio spending for the first time last year, rising by 60 per cent in the UK to over £ 650 million and taking spending on this medium to 3.9 per cent of the total UK market spend.

It is also forecast that spending for online advertising will rise by more than a third this year, a growth rate which is nearly 40 times faster than that of spending on the more traditional medium of direct mail.

Janet Chance, associate at Eversheds' Birmingham office, said: "Despite the benefits of broadband as a marketing medium, consumers have started to fight back against the increasing number of unwanted marketing spam they receive.

"There is a common misunderstanding that the internet is a place which is free of regulation; advertisers seem to think that the rules which govern the more traditional media such as TV and print don't apply."

In the UK, the Advertising Standards Authority (ASA) has been dealing with complaints made by consumers about marketing communications including online advertisements since 1995.

It endorses and administers the code issued by the Committee of Advertising Practice, which sets out flexible rules to address the issue. Although failure to comply with the code is not illegal, the ASA has the discretion to impose penalties for non-compliance with the code.

For instance, the ASA has recently warned a car dealer for sending unsolicited marketing e-mails and failing to provide free facilities to unsubscribe from future mailings.

The ASA found that the practice was in breach of the provision of the code which stipulates that advertisers can only send marketing e-mails if the recipient has consented to receiving such advertisement.

The code further states that the recipient's implied consent is not sufficient unless the person is an existing customer who has been given the opportunity to opt out.

On the facts, the advertiser failed to convince the ASA that the complainant expressly or impliedly consented to the practice or was a previous customer. The ASA further noted that the opt-out facility should have been in a working order and free of charge.