Can a sole trader use different business names?

[IndoEuro Interface]

If someone can advice me on:

1. Is it legal for a sole trader / self employed person to use different business names at the same time?

2. If it is legal, then does he/she have to complete any formalities with the HMRC?

Thanks in advance.

[MyAccountantOnline]

Its fine with HM Revenue & Customs if a soletrader has various different trading names - they are just noted on the tax return.