Yes. If it's from an unsolicited email it is a scam.

You can get around >10% at high risk doing ForEx, you can certainly make 20-odd percent if you gamble right, but like all gambles you can also lose all of it. These kinds of gains are for short term gamblers. Sure, you can bet big and if you hit it big you can say I told you so but for the most part you'd need someone who is incredibly well versed in a particular industry to second guess it.

If you don't expect to make enough profit to pay a personal accountant (hey they can be cheap around £150) every year, don't bother.