UK limited companies must register for Corporation Tax within 3 months of starting to do business. This includes buying, selling, advertising, renting a property, and employing someone. You can register for Corporation Tax here.

If your company is dormant, you must call HMRC and let them know that you will be dormant, so that they can make a note on your account and won't chase you for Corporation Tax.

HMRC phone numbers

• Inside the UK: 0300 200 3410
• Outside UK: +44 151 268 0571

You can also do this online here.