Please inform us as soon as possible, on the phone is fine. We will send you out a lost passbook form for you to sign and return to us. We will cancel the lost passbook, which means that if you find it later, you will not be able to use it to make withdrawals, and you should send it to us so we can destroy it. This is for your own security. We will send you out a new passbook to use. If there are any security issues around the loss of the book or you are worried it could have been stolen, we will close your account and open a new one with a new account number to avoid anyone fraudulently taking your money out. We reserve the right to make a £10 charge for lost passbooks.