Boiler-room scams have been around for decades, yet tricksters – often based overseas – still catch people out by persuading them to hand over tens or thousands or pounds for worthless shares. The carrot is always "a once-in-a-lifetime opportunity" or "get in now before the news is out". But the claims are always false and the only opportunity is for the fraudsters to fleece you.
The simple way to avoid becoming a victim is to ignore speculative emails or unsolicited phone calls. However, if you are tempted to invest with someone who contacts you, check them out before handing over cash. If they're not on the Financial Services Authority's Register then they're not authorised to sell you shares. That means if you deal with them, you'll have no recourse if things go wrong. Check the register at www.fsa.gov.uk/register.
Some crooks claim to be from a well-known firm that is on the register, but you can verify that by calling them back using the details on the register. Don't call them back using a number they've given you, because it could be anywhere. And if you are targeted, report the incident to the police and to the FSA on 0845 606 1234.