Do you mean you have lost your life in the uk test certificate; in that case you will have to take the test again:

http://lifeintheuktest.ukba.homeoffice.gov.uk/htmlsite/after_10.html

What happens if I lose my pass notification letter?
Your pass notification letter is very important: you should keep it in a safe place until you are ready to fill in your application for citizenship or indefinite leave to remain. If you lose this letter, you will not be given a new one to replace it. This means that you may have to pay to take the test again.

E Fidan
Administrator