Anne is correct Phil
Additionally, if you don't log-in for a long time you'll get an option to re-activate.

When you complete the registration details you'll see a message that says "Your registration details were created successfully. You have been sent an email with instructions on how to complete the registration process."

The e-mail is sent automatically very quicklyand will state:-

Dear Somebody

Your Visa4UK account has now been created. For security reasons, your account is currently locked.

Please click on following link or copy and paste the link below into your internet browser to unlock your account.

https://www.visa4uk.fco.gov.uk/accou...ation?code=you own personal code


When you click on that link you see this:-

Confirm Registration

Thank you for confirming your details. Your account has been unlocked and you should now be able to login with your password.]
Just click the log In button to login normally.

I'd suggest reviewing the FAQ's first you can find the webpage by following this link called Frequently Asked Question's

Good luck Phil