Spam emails, text messages and internet pop-ups are among the increasingly sophisticated ways fraudsters are finding their victims, according to the Office of Fair Trading (OFT).

As the government agency launched its 2007 Scams Awareness Month, it warned consumers the scammers are becoming increasingly ruthless and successful as these frauds are costing UK consumers around £3.5 billion each year.

Recent research commissioned by the OFT, involving 11,200 interviews, found that 1,388,000 UK consumers were the victim of a bogus prize draw or sweepstake, 400,000 of bogus holiday clubs, 330,000 of work at home scams, 200,000 of miracle health scams, 170,000 of clairvoyant and psychic scams and 110,000 of loan scams.

Mike Haley, head of Scambusters at the OFT, said: "Scammers are finding more ruthless and sophisticated ways to exploit modern tools such as the internet, email or text messaging.

"These scams deeply affect individuals and families, leading to debt, depression, and even suicide. Though anybody can be conned by the scammers, it is always the vulnerable, the oldest or youngest, who end up suffering the most."

The nationwide campaign, which will run throughout February, is part of an international initiative organised by the International Consumer Protection and Enforcement Network (Icpen).

To get its message across to the widest possible audience, the OFT has enlisted the support of local authority Trading Standards Services , Consumer Direct, the Advertising S ta ndards Authority and other consumer and industry bodies.

New methods to clamp down on the fraudsters include using new European laws, such as the Consumer Protection Cooperation Regulations, closer co-operation with authorities, as well as 'name and shaming' companies and individuals.

The OFT said the most common scams to look out for include:

Bogus holiday clubs – these cost UK consumers £1.17billion a year, with 400,000 victims each losing an average of £3,030. UK holidaymakers are invited to a presentation to collect a prize and pressurised into joining an exclusive holiday club, which does not deliver what it promises.

Prize draw and sweepstake scams – most are notifications of a cash prize in return for a fee. Respondents pay out the money but get no return, costing 380,000 UK consumers £60million every year.

Consumers can also be misled by letter, text or automated telephone message into thinking they have won a major prize, but must call a premium rate 090 number to claim, costing up to £1.50 a minute.

Nearly all end up with a low-value 'giveaway' item. More than a million people in the UK are scammed this way and lose £80m a year – an average of £80 each.

Miracle health and slimming cure scams – consumers receive a mailing or email promising a health 'miracle'. These pills, lotions, creams and other products supposedly cure everything from baldness and impotency to cancer or promise easy weight loss. Around £20million a year is spent on these scam products, which might even cause harm.

Clairvoyant mailings – although they are sent in their thousands, the letters from a so-called psychic or clairvoyant are personalised, offering predictions for payment. Seventy per cent of victims are women and the scam costs 170,000 adults in the UK £40million a year.

Fake foreign lotteries – consumers receive a letter, phone call, or email telling them they have won a major payout in an overseas lottery, and are asked to send money to cover administration or taxes. The winnings are never received, and cost 140,000 consumers £260 million every year.