The Office of Fair Trading yesterday revealed that "mass-marketed scams" were one of the five priority areas it would be focusing on over the next three years.

The OFT yesterday published its draft annual plan setting out its aims and objectives, and said stamping out swindles that have conned Britons out of millions of pounds was one of the crucial issues.

The watchdog said it intended to give priority to two scams: misleading ads that make false claims about health and beauty products, and the charlatan clairvoyants and psychics who write to people who are down on their luck in an attempt to persuade them to pay for their services.

Every year sees hundreds of complaints about potions and pills promising instant weight loss, enhanced sexual performance or "miracle cures" for serious illnesses and conditions such as baldness.

Meanwhile, a number of clairvoyant scams have come to the attention of police and trading standards officers. One involved a pair, "Lise and Rose", based in Geneva, who sent out letters offering clairvoyance sessions and "protecting crystals" for £30 - a swindle that came to light after white powder (the "crystals") leaked from an envelope, causing a security alert at a sorting office in Edinburgh.

However, the OFT said it would be taking action against other scams and promised to:

· continue its efforts to combat telephone lottery scams, many of which are based in Canada. The watchdog has already launched a campaign urging people not to hand over cash to callers who pretend the money will help unlock massive winnings on the Canadian national lottery. One British victim lost £67,000;

· identify any misleading or deceptive prize draw mailings originating from within the UK and consider action under the control of misleading advertisements regulations;